Method for producing contact lenses with durable lubricious coatings thereon

ABSTRACT

The invention is related to a method for producing silicone hydrogel contact lenses with having a stable coating thereon. A method of the invention comprises a water-based coating process (step) for forming a relatively-stable base coating of a homo- or copolymer of acrylic acid or C 1 -C 3  alkylacrylic acid onto a silicone hydrogel contact lens made from a lens formulation comprising from about 35% to about 60% by weight of N-vinylpyrrolidone.

This application claims the benefits under 35 USC §119 (e) of U.S. provisional application No. 62/158,045 filed May 7, 2015, incorporated by reference in its entirety.

The present invention generally relates to a method for producing silicone hydrogel contact lenses having a stable coating thereon involving a coating step carried out in a cost-effective and time-efficient manner. In addition, the present invention provides silicone hydrogel contact lenses produced according to the method of the invention.

BACKGROUND

Soft silicone hydrogel contact lenses are increasingly becoming popular because of their high oxygen permeability and comfort. But, a silicone hydrogel material typically has a surface, or at least some areas of its surface, which is hydrophobic (non-wettable) and susceptible to adsorbing lipids or proteins from the ocular environment and may adhere to the eye. Thus, a silicone hydrogel contact lens will generally require a surface modification.

Recently, a new cost-effective approach has been described in U.S. pat. Appl. pub. No. 2012/0026457 A1 for applying a non-silicone hydrogel coating onto a silicone hydrogel contact lens, in which an organic solvent-based coating solution of a polyanionic polymer is involved in forming an interpenetrating base coating (i.e., an anchoring layer) on a silicone hydrogel contact lens and then a partially-crosslinked hydrophilic polymeric material are covalently attached onto the anchoring layer directly in a lens package during autoclave. Silicone hydrogel contact lenses produced according to such an approach can have a water-gradient structural configuration and a soft and lubricious surface.

However, the resultant silicone hydrogel contact lenses may be susceptible to high deposition and accumulation of positively charged antimicrobials (e.g., polyhexamethylene biguanide, Polyquaternium-1®, or the like) commonly found in most multipurpose lens care solutions, due to the presence of the anchoring layer of a polyanionic material. Those positively charged antimicrobials adsorbed by the silicone hydrogel lenses may be released into the eye and may cause undesirable clinical symptoms in some persons, such as diffuse corneal staining and product intolerance, when the lenses are worn by patients.

Therefore, there is still a need for a method for producing silicone hydrogel contact lenses with a durable non-silicone hydrogel coating which has a minimized susceptibility to high deposition and accumulation of positively charged antimicrobials. There is also a need for silicone hydrogel contact lenses with such a durable coating thereon.

SUMMARY OF THE INVENTION

The invention, in one aspect, provides a method for producing silicone hydrogel contact lenses each having a crosslinked hydrophilic coating thereon, the method of invention comprising the steps of: (a) obtaining a silicone hydrogel contact lens including a polymer which is a polymerization product of a polymerizable composition comprising (i) at least one siloxane-containing vinylic monomer, (ii) a polysiloxane vinylic crosslinker, and (iii) at least about 25% by weight of one or more hydrophilic vinylic monomers relative to the total amount of polymerizable components, wherein said one or more hydrophilic vinylic monomers are selected from the group consisting of N,N-dimethylacrylamide (DMA), N,N-dimethylmethacrylamide (DMMA), 2-acrylamidoglycolic acid, N-hydroxypropylacrylamide, N-hydroxyethyl acrylamide, N-[tris(hydroxymethyl)methyl]-acrylamide, N-vinylpyrrolidone, N-vinyl formamide, N-vinyl acetamide, N-vinyl isopropylamide, N-vinyl-N-methyl acetamide, N-methyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone, 5-methyl-3-methylene-2-pyrrolidone, and a combination thereof; (b) contacting the silicone hydrogel contact lens with an organic solvent-based solution of polymethacrylic acid for a time period of from about 30 seconds to about 120 seconds to form a base coating; (c) contacting the silicone hydrogel contact lens obtained in step (b) with a polyamidoamine-epichlorohydrin solution (hereinafter designated as a “PAE solution”) for a time period of from about 30 seconds to about 300 seconds (preferably from about 35 second to about 200 seconds, more preferably from about 40 seconds to about 120 seconds) to form a polyamidoamine-epichlorohydrin-doped base coating (hereinafter designated as a “PAE-doped base coating”) on the silicone hydrogel contact lens, wherein the PAE solution comprises from about 0.001% to about 5% by weight (preferably from about 0.01% to about 2.5% by weight, more preferably from about 0.1% to about 1.5% by weight) of a polyamidoamine-epichlorohydrin dissolved in water or in a mixture of water and an organic solvent relative to the total weight of the PAE solution and having a pH of from about 2.0 to about 3.5 (preferably from about 2.0 to about 3.0, more preferably from about 2.0 to about 2.5); (d) heating the silicone hydrogel contact lens with the PAE-doped base coating thereon, which is obtained in step (c), in an aqueous solution which comprises a water-soluble and thermally-crosslinkable hydrophilic polymeric material having azetidinium groups and optionally (but preferably) amino or carboxyl groups, to and at a temperature of from about 60° C. to about 140° C. for a time period sufficient long to crosslink the polymethacrylic acid, the polyamidoamine-epichlorohydrin and the hydrophilic polymeric material, thereby forming a hydrogel coating on the silicone hydrogel contact lens, wherein the hydrogel coating on the silicone hydrogel contact lens has a durability as characterized by having a lubricity better than the control coating on a control lens after being subjected to 30 cycles of digital rubbing tests, wherein the control lens is the silicone hydrogel contact lens and the control coating on the control lens is obtained according to a process in which only step (c) listed above is eliminated whereas other steps and conditions listed above are unchanged.

In another aspect, the invention provides a silicone hydrogel contact lens obtained according to a method of the invention, wherein the silicone hydrogel contact lens has an oxygen permeability of at least about 40 barrers, a surface wettability characterized by a water contact angle of about 100 degrees or less, and a coating durability characterized by surviving a digital rubbing test.

These and other aspects of the invention will become apparent from the following description of the presently preferred embodiments. The detailed description is merely illustrative of the invention and does not limit the scope of the invention, which is defined by the appended claims and equivalents thereof. As would be obvious to one skilled in the art, many variations and modifications of the invention may be effected without departing from the spirit and scope of the novel concepts of the disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Generally, the nomenclature used herein and the laboratory procedures are well known and commonly employed in the art. Conventional methods are used for these procedures, such as those provided in the art and various general references. Where a term is provided in the singular, the inventors also contemplate the plural of that term. The nomenclature used herein and the laboratory procedures described below are those well-known and commonly employed in the art.

“Contact Lens” refers to a structure that can be placed on or within a wearer's eye. A contact lens can correct, improve, or alter a user's eyesight, but that need not be the case. A contact lens can be of any appropriate material known in the art or later developed, and can be a soft lens, a hard lens, or a hybrid lens. A “silicone hydrogel contact lens” refers to a contact lens comprising a silicone hydrogel bulk (core) material.

A “hydrogel” or “hydrogel material” refers to a crosslinked polymeric material which is insoluble in water, but can hold at least 10 percent by weight of water in its three-dimensional polymer networks (i.e., polymer matrix) when it is fully hydrated.

A “silicone hydrogel” refers to a silicone-containing hydrogel obtained by copolymerization of a polymerizable composition comprising at least one silicone-containing monomer or at least one silicone-containing macromer or at least one crosslinkable silicone-containing prepolymer.

As used in this application, the term “non-silicone hydrogel” refers to a hydrogel that is theoretically free of silicon.

“Hydrophilic,” as used herein, describes a material or portion thereof that will more readily associate with water than with lipids.

A “vinylic monomer” refers to a compound that has one sole ethylenically unsaturated group, is soluble in a solvent, and can be polymerized actinically or thermally.

The term “soluble”, in reference to a compound or material in a solvent, means that the compound or material can be dissolved in the solvent to give a solution with a concentration of at least about 0.5% by weight at room temperature (i.e., a temperature of about 22° C. to about 28° C.).

The term “insoluble”, in reference to a compound or material in a solvent, means that the compound or material can be dissolved in the solvent to give a solution with a concentration of less than 0.005% by weight at room temperature (as defined above).

As used in this application, the term “ethylenically unsaturated group” is employed herein in a broad sense and is intended to encompass any groups containing at least one >C═C< group. Exemplary ethylenically unsaturated groups include without limitation (meth)acryloyl

allyl, vinyl, styrenyl, or other C═C containing groups.

The term “(meth)acrylamide” refers to methacrylamide and/or acrylamide.

The term “(meth)acrylate” refers to methacrylate and/or acrylate.

As used herein, “actinically” in reference to curing, crosslinking or polymerizing of a polymerizable composition, a prepolymer or a material means that the curing (e.g., crosslinked and/or polymerized) is performed by actinic irradiation, such as, for example, UV/visible irradiation, ionizing radiation (e.g. gamma ray or X-ray irradiation), microwave irradiation, and the like. Thermal curing or actinic curing methods are well-known to a person skilled in the art.

A “hydrophilic vinylic monomer”, as used herein, refers to a vinylic monomer which as a homopolymer typically yields a polymer that is water-soluble or can absorb at least 10 percent by weight of water.

A “hydrophobic vinylic monomer”, as used herein, refers to a vinylic monomer which as a homopolymer typically yields a polymer that is insoluble in water and can absorb less than 10 percent by weight of water.

A “macromer” or “prepolymer” refers to a compound or polymer that contains ethylenically unsaturated groups and has an average molecular weight of greater than 700 Daltons.

As used in this application, the term “vinylic crosslinker” refers to a compound having at least two ethylenically unsaturated groups. A “vinylic crosslinking agent” refers to a vinylic crosslinker having a molecular weight of 700 Daltons or less.

As used in this application, the term “polymer” means a material formed by polymerizing/crosslinking one or more monomers or macromers or prepolymers or combinations thereof.

As used in this application, the term “molecular weight” of a polymeric material (including monomeric or macromeric materials) refers to the weight-average molecular weight unless otherwise specifically noted or unless testing conditions indicate otherwise.

A “polysiloxane” refers to a compound containing a polysiloxane segment of

in which m1 and m2 independently of each other are an integer of from 0 to 500 and (m1+m2) is from 2 to 500, R₁′, R₂′, R₃′, R₄′, R₅′, R₆′, R₇′, and R₈′ independently of one another, are C₁-C₁₀ alkyl, C₁-C₄ alkyl- or C₁-C₄-alkoxy-substituted phenyl, C₁-C₁₀ fluoroalkyl, C₁-C₁₀ fluoroether, C₆-C₁₈ aryl radical, -alk-(OC₂H₄)_(m3)—OR′ (in which alk is C₁-C₆ alkyl diradical, R′ is H or C₁-C₄ alkyl and m3 is an integer from 1 to 10), a C₄-C₄₀ hydrocarbon radical having one or more hydroxyl groups, or a linear hydrophilic polymer chain.

A “polycarbosiloxane” refers to a compound containing one sole polycarbosiloxane segment of

in which n1 is an integer of 2 or 3, n2 is an integer of from 2 to 100 (preferably from 2 to 20, more preferably from 2 to 10, even more preferably from 2 to 6), R₁″, R₂″, R₃″, R₄″, R₅″, and R₆″ independent of one another are a C₁-C₆ alkyl radical (preferably methyl).

The term “fluid” as used herein indicates that a material is capable of flowing like a liquid.

The term “alkyl” refers to a monovalent radical obtained by removing a hydrogen atom from a linear or branched alkane compound. An alkyl group (radical) forms one bond with one other group in an organic compound.

The term “alkylene divalent group” or “alkylene diradical” or “alkyl diradical” interchangeably refers to a divalent radical obtained by removing one hydrogen atom from an alkyl. An alkylene divalent group forms two bonds with other groups in an organic compound.

The term “alkyl triradical” refers to a trivalent radical obtained by removing two hydrogen atoms from an alkyl. An alkyl triradical forms three bonds with other groups in an organic compound.

The term “alkoxy” or “alkoxyl” refers to a monovalent radical obtained by removing the hydrogen atom from the hydroxyl group of a linear or branched alkyl alcohol. An alkoxy group (radical) forms one bond with one other group in an organic compound.

In this application, the term “substituted” in reference to an alkyl diradical or an alkyl radical means that the alkyl diradical or the alkyl radical comprises at least one substituent which replaces one hydrogen atom of the alkyl diradical or the alkyl radical and is selected from the group consisting of hydroxy (—OH), carboxy (—COOH), —NH₂, sulfhydryl (—SH), C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio (alkyl sulfide), C₁-C₄ acylamino, C₁-C₄ alkylamino, di-C₁-C₄ alkylamino, halogen atom (Br or Cl), and combinations thereof.

In this application, an “oxazoline” refers to a compound of

in which: R¹ is hydrogen, methyl, ethyl, N-pyrrolidonylmethyl, N-pyrrolidonylethyl, N-pyrrolidonylpropyl, or a monovalent radical of -alk-(OC₂H₄)_(m3)—OR″ in which alk is C₁-C₄ alkyl diradical; R″ is C₁-C₄ alkyl (preferably methyl); and m3 is an integer from 1 to 10 (preferably 1 to 5).

In this application, the term “polyoxazoline” refers to a polymer or polymer segment of

in which: R¹ is hydrogen, methyl, ethyl, N-pyrrolidonylmethyl, N-pyrrolidonylethyl, N-pyrrolidonylpropyl, or a monovalent radical of -alk-(OC₂H₄)_(m3)—OR″ in which alk is C₁-C₄ alkyl diradical; R″ is C₁-C₄ alkyl (preferably methyl); m3 is an integer from 1 to 10 (preferably 1 to 5); x is an integer from 5 to 500.

In this application, the term “poly(2-oxazoline-co-ethyleneimine)” refers to a statistical copolymer or a polymer segment thereof having a formula of

in which: R¹ is hydrogen, methyl, ethyl, N-pyrrolidonylmethyl, N-pyrrolidonylethyl, N-pyrrolidonylpropyl, or a monovalent radical of -alk-(OC₂H₄)_(m3)—OR″ in which alk is C₁-C₄ alkyl diradical; R″ is C₁-C₄ alkyl (preferably methyl); m3 is an integer from 1 to 10 (preferably 1 to 5); x is an integer from 5 to 500; z is an integer equal to or less than x. A poly(2-oxazoline-co-ethyleneimine) is obtained by hydrolyzing a polyoxazoline.

In this application, the term “poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin” refers to a polymer obtained by reacting a poly(2-oxazoline-co-ethyleneimine) with epichlorohydrin to convert all or substantial percentage (≧90%) of the secondary amine groups of the poly(2-oxazoline-co-ethyleneimine) into azetidinium groups. Examples of poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin are disclosed in a copending U.S. patent application No. 62/041,762 filed 26 Aug. 2014.

An “epichlorohydrin-functionalized polyamine” or “epichlorohydrin-functionalized polyamidoamine” refers to a polymer obtained by reacting a polyamine or polyamidoamine with epichlorohydrin to convert all or a substantial percentage of the secondary amine groups of the polyamine or polyamidoamine into azetidinium groups.

The term “polyamidoamine-epichlorohydrin” refers to an epichlorohydrin-functionalized adipic acid-diethylenetriamine copolymer.

In this application the term “azetidinium” or “3-hydroxyazetidinium” refers to a positively-charged, divalent radical (or group or moiety) of

The term “thermally-crosslinkable” in reference to a polymeric material or a functional group means that the polymeric material or the functional group can undergo a crosslinking (or coupling) reaction with another material or functional group at a relatively-elevated temperature (from about 40° C. to about 140° C.), whereas the polymeric material or functional group cannot undergo the same crosslinking reaction (or coupling reaction) with another material or functional group at room temperature (i.e., from about 22° C. to about 28° C., preferably from about 24° C. to about 26° C., in particular at about 25° C.) to an extend detectable for a period of about one hour.

The term “azlactone” refers to a mono-valent radical of formula

in which p is 0 or 1; ³R and ⁴R independently of each other is C₁-C₈ alkyl (preferably methyl).

As used in this application, the term “phosphorylcholine” refers to a monovalent zwitterionic group of

in which t1 is an integer of 1 to 5 and R₁″, R₂″ and R₃″ independently of one another are C₁-C₈ alkyl or C₁-C₈ hydroxyalkyl.

As used in this application, the term “reactive vinylic monomer” refers to any vinylic monomer having at least one reactive functional group selected from the group consisting of carboxyl group, primary amino group, and secondary amino group.

As used in this application, the term “non-reactive vinylic monomer” refers to any vinylic monomer (either hydrophilic or hydrophobic vinylic monomer) free of carboxyl group, primary amino group, secondary amino group, epoxide group, isocyanate group, azlactone group, or aziridine group.

A free radical initiator can be either a photoinitiator or a thermal initiator. A “photoinitiator” refers to a chemical that initiates free radical crosslinking/polymerizing reaction by the use of light. A “thermal initiator” refers to a chemical that initiates radical crosslinking/polymerizing reaction by the use of heat energy.

A “spatial limitation of actinic radiation” refers to an act or process in which energy radiation in the form of rays is directed by, for example, a mask or screen or combinations thereof, to impinge, in a spatially restricted manner, onto an area having a well-defined peripheral boundary. A spatial limitation of UV radiation is obtained by using a mask or screen having a radiation (e.g., UV) permeable region, a radiation (e.g., UV) impermeable region surrounding the radiation-permeable region, and a projection contour which is the boundary between the radiation-impermeable and radiation-permeable regions, as schematically illustrated in the drawings of U.S. Pat. No. 6,800,225 (FIGS. 1-11), and U.S. Pat. No. 6,627,124 (FIGS. 1-9), U.S. Pat. No. 7,384,590 (FIGS. 1-6), and U.S. Pat. No. 7,387,759 (FIGS. 1-6). The mask or screen allows to spatially projects a beam of radiation (e.g., UV radiation) having a cross-sectional profile defined by the projection contour of the mask or screen. The projected beam of radiation (e.g., UV radiation) limits radiation (e.g., UV radiation) impinging on a lens formulation located in the path of the projected beam from the first molding surface to the second molding surface of a mold. The resultant contact lens comprises an anterior surface defined by the first molding surface, an opposite posterior surface defined by the second molding surface, and a lens edge defined by the sectional profile of the projected UV beam (i.e., a spatial limitation of radiation). The radiation used for the crosslinking is radiation energy, especially UV radiation, gamma radiation, electron radiation or thermal radiation, the radiation energy preferably being in the form of a substantially parallel beam in order on the one hand to achieve good restriction and on the other hand efficient use of the energy.

A “water contact angle” refers to an average water contact angle (i.e., contact angles measured by Sessile Drop method) at the room temperature, which is obtained by averaging measurements of contact angles with at least 3 individual contact lenses.

The term “intactness” in reference to a coating on a silicone hydrogel contact lens is intended to describe the extent to which the contact lens can be stained by Sudan Black in a Sudan Black staining test described in Example 1. Good intactness of the coating on a silicone hydrogel contact lens means that there is practically no Sudan Black staining of the contact lens.

The term “durability” in reference to a coating on a silicone hydrogel contact lens is intended to describe that the coating on the silicone hydrogel contact lens can survive a digital rubbing test.

As used herein, “surviving a digital rubbing test” or “surviving a durability test” in reference to a coating on a contact lens means that after digitally rubbing the lens according to a procedure described in Example 1, water contact angle on the digitally rubbed lens is still about 100 degrees or less, preferably about 90 degrees or less, more preferably about 80 degrees or less, most preferably about 70 degrees or less.

The intrinsic “oxygen permeability”, Dk, of a material is the rate at which oxygen will pass through a material. As used in this application, the term “oxygen permeability (Dk)” in reference to a hydrogel (silicone or non-silicone) or a contact lens means a measured oxygen permeability (Dk) which is corrected for the surface resistance to oxygen flux caused by the boundary layer effect according to the procedures described in Example 1 of 2012/0026457 A1. Oxygen permeability is conventionally expressed in units of barrers, where “barrer” is defined as [(cm³ oxygen)(mm)/(cm²)(sec)(mm Hg)]×10⁻¹⁰.

The “oxygen transmissibility”, Dk/t, of a lens or material is the rate at which oxygen will pass through a specific lens or material with an average thickness of t [in units of mm] over the area being measured. Oxygen transmissibility is conventionally expressed in units of barrers/mm, where “barrers/mm” is defined as [(cm³ oxygen)/(cm²)(sec)(mm Hg)]×10⁻⁹.

The “ion permeability” through a lens correlates with the Ionoflux Diffusion Coefficient. The Ionoflux Diffusion Coefficient, D (in units of [mm²/min]), is determined by applying Fick's law as follows:

D=−n′/(A×dc/dx)

where n′=rate of ion transport [mol/min]; A=area of lens exposed [mm²]; dc=concentration difference [mol/L]; dx=thickness of lens [mm].

“Ophthalmically compatible”, as used herein, refers to a material or surface of a material which may be in intimate contact with the ocular environment for an extended period of time without significantly damaging the ocular environment and without significant user discomfort.

The term “ophthalmically safe” with respect to a packaging solution for sterilizing and storing contact lenses is meant that a contact lens stored in the solution is safe for direct placement on the eye without rinsing after autoclave and that the solution is safe and sufficiently comfortable for daily contact with the eye via a contact lens. An ophthalmically-safe packaging solution after autoclave has a tonicity and a pH that are compatible with the eye and is substantially free of ocularly irritating or ocularly cytotoxic materials according to international ISO standards and U.S. FDA regulations.

The term “modulus” or “elastic modulus” in reference to a contact lens or a material means the tensile modulus or Young's modulus which is a measure of the stiffness of a contact lens or a material. The modulus can be measured using a method in accordance with ANSI Z80.20 standard. A person skilled in the art knows well how to determine the elastic modulus of a silicone hydrogel material or a contact lens. For example, all commercial contact lenses have reported values of elastic modulus.

An “organic-based solution” refers to a solution which is a homogeneous mixture consisting of an organic-based solvent and one or more solutes dissolved in the organic based solvent. An organic-based coating solution refers to an organic-based solution containing at least one polymeric coating material as a solute in the solution.

An “organic-based solvent” is intended to describe a solvent system which consists of one or more organic solvents and about 40% or less, preferably about 30% or less, more preferably about 20% or less, even more preferably about 10% or less, in particular about 5% or less by weight of water relative to the weight of the solvent system.

The invention is generally related to a method for producing silicone hydrogel contact lenses with a non-silicone hydrogel coating thereon, wherein the resultant non-silicone hydrogel coating has a minimized susceptibility to deposition and accumulation of positively charged antimicrobials and also an improved durability.

The invention, in one aspect, provides a method for producing silicone hydrogel contact lenses each having a crosslinked hydrophilic coating thereon, the method of invention comprising the steps of: (a) obtaining a silicone hydrogel contact lens including a polymer which is a polymerization product of a polymerizable composition comprising (i) at least one siloxane-containing vinylic monomer, (ii) a polysiloxane vinylic crosslinker, and (iii) at least about 25% by weight (preferably at least about 30% by weight, more preferably at least about 35% by weight, even more preferably at least about 40% by weight) of one or more hydrophilic vinylic monomers relative to the total amount of polymerizable components, wherein said one or more hydrophilic vinylic monomers are selected from the group consisting of N,N-dimethylacrylamide (DMA), N,N-dimethylmethacrylamide (DMMA), 2-acrylamidoglycolic acid, N-hydroxypropylacrylamide, N-hydroxyethyl acrylamide, N-[tris(hydroxymethyl)methyl]-acrylamide, N-vinylpyrrolidone, N-vinyl formamide, N-vinyl acetamide, N-vinyl isopropylamide, N-vinyl-N-methyl acetamide, N-methyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone, 5-methyl-3-methylene-2-pyrrolidone, and a combination thereof; (b) contacting the silicone hydrogel contact lens with an organic solvent-based solution of polymethacrylic acid for a time period of from about 30 seconds to about 120 seconds (preferably from about 35 second to about 100 seconds, more preferably from about 40 seconds to about 80 seconds) to form a base coating; (c) contacting the silicone hydrogel contact lens obtained in step (b) with a PAE solution for a time period of from about 30 seconds to about 300 seconds (preferably from about 35 second to about 200 seconds, more preferably from about 40 seconds to about 120 seconds) to form a PAE-doped base coating on the silicone hydrogel contact lens, wherein the PAE solution comprises from about 0.001% to about 5% by weight (preferably from about 0.01% to about 2.5% by weight, more preferably from about 0.1% to about 1.5% by weight) of a polyamidoamine-epichlorohydrin dissolved in water or in a mixture of water and an organic solvent relative to the total weight of the PAE solution and having a pH of from about 2.0 to about 3.5 (preferably from about 2.0 to about 3.0, more preferably from about 2.0 to about 2.5); (d) heating the silicone hydrogel contact lens with the PAE-doped base coating thereon, which is obtained in step (c), in an aqueous solution which comprises a water-soluble and thermally-crosslinkable hydrophilic polymeric material having azetidinium groups and amino or carboxyl groups, to and at a temperature of from about 60° C. to about 140° C. for a time period sufficient long to crosslink the polymethacrylic acid, the polyamidoamine-epichlorohydrin and the hydrophilic polymeric material, thereby forming a hydrogel coating on the silicone hydrogel contact lens, wherein the hydrogel coating on the silicone hydrogel contact lens has a durability as characterized by having a lubricity better than the control coating on a control lens after being subjected to 30 cycle of digital rubbing tests, wherein the control lens is the silicone hydrogel contact lens and the control coating on the control lens is obtained according to a process in which only step (c) listed above is eliminated whereas other steps and conditions listed above are unchanged.

A person skilled in the art knows very well how to make silicone hydrogel (SiHy) contact lenses. For example, SiHy contact lenses can be produced in a conventional “spin-casting mold,” as described for example in U.S. Pat. No. 3,408,429, or by the full cast-molding process in a static form, as described in U.S. Pat. Nos. 4,347,198; 5,508,317; 5,583,463; 5,789,464; and 5,849,810, or by lathe cutting of silicone hydrogel buttons as used in making customized contact lenses. In cast-molding, a lens formulation typically is dispensed into molds and cured (i.e., polymerized and/or crosslinked) in molds for making contact lenses. For production of silicone hydrogel (SiHy) contact lenses, a SiHy lens-forming composition (or SiHy lens formulation) for cast-molding or spin-cast molding or for making SiHy rods used in lathe-cutting of contact lenses generally comprises at least one components selected from the group consisting of a silicone-containing vinylic monomer, a silicone-containing vinylic macromer, a silicone-containing prepolymer, a hydrophilic vinylic monomer, a hydrophobic vinylic monomer, a vinylic crosslinking agent (a compound having a molecular weight of about 700 Daltons or less and containing at least two ethylenically unsaturated groups), a free-radical initiator (photoinitiator or thermal initiator), a hydrophilic vinylic macromer/prepolymer, and combination thereof, as well known to a person skilled in the art. A SiHy contact lens formulation can also comprise other necessary components known to a person skilled in the art, such as, for example, a UV-absorbing agent (i.e., UV-absorbing vinylic monomers), a visibility tinting agent (e.g., dyes, pigments, or mixtures thereof), antimicrobial agents (e.g., preferably silver nanoparticles), a bioactive agent, leachable lubricants, leachable tear-stabilizing agents, and mixtures thereof, as known to a person skilled in the art. Resultant SiHy contact lenses then can be subjected to extraction with an extraction solvent to remove unpolymerized components from the resultant lenses and to hydration process, as known by a person skilled in the art. In addition, a preformed SiHy contact lens can be a colored contact lens (i.e., a SiHy contact lens having at least one colored patterns printed thereon as well known to a person skilled in the art).

Any suitable silicone-containing vinylic monomers can be used in the invention. Preferred silicone-containing vinylic monomers are three classes of vinylic monomers: a class of vinylic monomers each having a tris(trialkylsilyloxy)silylalkyl group, another class of vinylic monomers each having a bis(trialkylsilyloxy)alkylsilylalkyl group, and a further class of vinylic monomers each having a polydimethylsiloxane segment of

in which n1 is an integer of from 2 to 100.

Examples of these three classes of preferred silicone-containing vinylic monomers include without limitation N-[tris(trimethylsiloxy)silylpropyl] (meth)acrylamide, N-[tris(dimethylpropylsiloxy)silylpropyl] (meth)acrylamide, N-[tris(dimethylphenylsiloxy)silyl-propyl] (meth)acrylamide, N-[tris(dimethylethylsiloxy)silylpropyl] (meth)acrylamide, N-[methylbis(trimethylsiloxy)silyl]propyl (meth)acrylamide, N-methyl-N-[methyl-bis(trimethylsiloxy)silyl]propyl (meth)acrylamide N-(2-hydroxy-3-(3-(bis(trimethylsilyloxy)-methylsilyl)propyloxy)propyl)-2-methyl acrylamide; N-(2-hydroxy-3-(3-(bis(trimethylsilyloxy)-methylsilyl)propyloxy)propyl) acrylamide; N,N-bis[2-hydroxy-3-(3-(bis(trimethylsilyloxy)-methylsilyl)propyloxy)propyl]-2-methyl acrylamide; N,N-bis[2-hydroxy-3-(3-(bis(trimethylsilyloxy)-methylsilyl)propyloxy)propyl] acrylamide; N-(2-hydroxy-3-(3-(tris(trimethylsilyloxy)silyl)-propyloxy)propyl)-2-methyl acrylamide; N-(2-hydroxy-3-(3-(tris(trimethylsilyloxy)silyl)propyloxy)-propyl)acrylamide; N,N-bis[2-hydroxy-3-(3-(tris(trimethylsilyloxy)silyl)propyloxy)propyl]-2-methyl acrylamide; N,N-bis[2-hydroxy-3-(3-(tris(trimethylsilyloxy)silyl)propyloxy)propyl]acrylamide; N-[2-hydroxy-3-(3-(t-butyl-dimethylsilyl)propyloxy)propyl]-2-methyl acrylamide; N-[2-hydroxy-3-(3-(t-butyldimethylsilyl)-propyloxy) propyl]acrylamide; N,N-bis[2-hydroxy-3-(3-(t-butyldimethylsilyl)propyloxy)propyl]-2-methyl acrylamide; N,N-bis[2-hydroxy-3-(3-(t-butyldimethylsilyl)propyloxy)propyl] acrylamide; 3-methacryloxy propylpentamethyldisiloxane, tris(trimethylsilyloxy)silylpropyl methacrylate (TRIS), (3-methacryloxy-2-hydroxypropyloxy)propylbis(trimethylsiloxy)-methylsilane), (3-methacryloxy-2-hydroxypropyloxy)propyltris(trimethylsiloxy)silane, 3-methacryloxy-2-(2-hydroxyethoxy)-propyloxy)propylbis(trimethylsiloxy)methylsilane, N-2-methacryloxyethyl-O-(methyl-bis-trimethylsiloxy-3-propyl)silylcarbamate, 3-(trimethylsilyl)-propylvinyl carbonate, 3-(vinyloxycarbonylthio)propyl-tris(trimethyl-siloxy)silane, 3-[tris(trimethyl-siloxy)silyl]propylvinyl carbamate, 3-[tris(trimethylsiloxy)silyl] propyl allyl carbamate, 3-[tris(trimethylsiloxy)silyl]propyl vinyl carbonate, t-butyldimethyl-siloxyethyl vinyl carbonate; trimethylsilylethyl vinyl carbonate, and trimethylsilylmethyl vinyl carbonate; mono-(meth)acryloyl-terminated, mono-C₁-C₄ alkyl-terminated polydimethylsiloxanes of various molecular weight (e.g., mono-3-methacryloxypropyl terminated, mono-butyl terminated polydimethylsiloxane or mono-(3-methacryloxy-2-hydroxypropyloxy)propyl terminated, mono-butyl terminated polydimethylsiloxane); mono-vinylcarbonate-terminated, mono-C₁-C₄ alkyl-terminated polydimethylsiloxanes; mono-vinylcarbamate-terminated, mono-C₁-C₄ alkyl-terminated polydimethylsiloxane; mono-methacrylamide-terminated, mono-C₁-C₄ alkyl-terminated polydimethylsiloxanes; mono-acrylamide-terminated, mono-C₁-C₄ alkyl-terminated polydimethylsiloxanes; combinations thereof.

Any suitable polysiloxane vinylic crosslinkers (macromers) can be used in the invention. Examples of preferred polysiloxane vinylic crosslinkers are dimethacrylated or diacrylated polydimethylsiloxanes of various molecular weight; di-vinyl carbonate-terminated polydimethylsiloxanes; di-vinyl carbamate-terminated polydimethylsiloxane; di-methacrylamide-terminated polydimethylsiloxanes; di-acrylamide-terminated polydimethylsiloxanes; bis-3-methacryloxy-2-hydroxypropyloxypropyl polydimethylsiloxane; N,N,N′,N′-tetrakis(3-methacryloxy-2-hydroxypropyl)-alpha,omega-bis-3-aminopropyl-polydimethylsiloxane; polysiloxanylalkyl (meth)acrylic monomers; siloxane-containing macromer selected from the group consisting of Macromer A, Macromer B, Macromer C, and Macromer D described in U.S. Pat. No. 5,760,100; chain-extended polysiloxabe vinylic crosslinkers disclosed in US201008843A1 and US20120088844A1; the reaction products of glycidyl methacrylate with amino-functional polydimethylsiloxanes; hydroxyl-functionalized siloxane-containing vinylic monomers or macromers; polysiloxane-containing macromers disclosed in U.S. Pat. Nos. 4,136,250, 4,153,641, 4,182,822, 4,189,546, 4,343,927, 4,254,248, 4,355,147, 4,276,402, 4,327,203, 4,341,889, 4,486,577, 4,543,398, 4,605,712, 4,661,575, 4,684,538, 4,703,097, 4,833,218, 4,837,289, 4,954,586, 4,954,587, 5,010,141, 5,034,461, 5,070,170, 5,079,319, 5,039,761, 5,346,946, 5,358,995, 5,387,632, 5,416,132, 5,451,617, 5,486,579, 5,962,548, 5,981,675, 6,039,913, and 6,762,264; polysiloxane-containing macromers disclosed in U.S. Pat. Nos. 4,259,467, 4,260,725, and 4,261,875.

In accordance with the invention, a polymerizable composition must comprise at least about 25% by weight of one or more hydrophilic vinylic monomers relative to the total amount of polymerizable components, wherein said one or more hydrophilic vinylic monomers are selected from the group consisting of N,N-dimethylacrylamide (DMA), N,N-dimethylmethacrylamide (DMMA), 2-acrylamidoglycolic acid, N-hydroxypropylacrylamide, N-hydroxyethyl acrylamide, N-[tris(hydroxymethyl)methyl]-acrylamide, N-vinylpyrrolidone, N-vinyl formamide, N-vinyl acetamide, N-vinyl isopropylamide, N-vinyl-N-methyl acetamide, N-methyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone, 5-methyl-3-methylene-2-pyrrolidone, and a combination thereof. It is believed that monomeric units formed from the above-listed hydrophilic vinylic monomer in the lens material can interact with the carboxyl groups of polymethacrylic acid in the base coating through either ionic/polar interaction or hydrogen bonding to maintain an affinity to the lens material.

In accordance with the invention, a polymerizable composition can further comprise one or more hydrophilic vinylic monomers other than those listed above. Preferred examples of such hydrophilic vinylic monomers are 2-hydroxyethylmethacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), hydroxypropyl acrylate, hydroxypropyl methacrylate (HPMA), trimethylammonium 2-hydroxy propylmethacrylate hydrochloride, aminopropyl methacrylate hydrochloride, dimethylaminoethyl methacrylate (DMAEMA), glycerol methacrylate (GMA), a C₁-C₄-alkoxy polyethylene glycol (meth)acrylate having a weight average molecular weight of up to 1500, methacrylic acid, and mixtures thereof.

A polymerizable composition can further comprise one or more components selected from the group consisting of a hydrophobic vinylic monomer, a vinylic crosslinking agent, a UV-absorbing vinylic monomer, a free-radical initiator (thermal initiator or photoinitiator), a bioactive agent, a leachable lubricant, a leachable tear-stabilizing agent, and combinations thereof.

Examples of preferred hydrophobic vinylic monomers include methylacrylate, ethyl-acrylate, propylacrylate, isopropylacrylate, cyclohexylacrylate, 2-ethylhexylacrylate, methylmethacrylate, ethylmethacrylate, propylmethacrylate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, styrene, chloroprene, vinyl chloride, vinylidene chloride, acrylonitrile, 1-butene, butadiene, methacrylonitrile, vinyl toluene, vinyl ethyl ether, perfluorohexylethyl-thio-carbonyl-aminoethyl-methacrylate, isobornyl methacrylate, trifluoroethyl methacrylate, hexafluoro-isopropyl methacrylate, hexafluorobutyl methacrylate.

Examples of preferred vinylic crosslinking agents include without limitation di-(meth)acrylate-terminated polyethylene glycol, di-(meth)acrylate-terminated polyoxyethylene-polyoxypropylene block copolymer, tetraethyleneglycol diacrylate, triethyleneglycol diacrylate, diethyleneglycol diacrylate, ethyleneglycol diacrylate, tetraethyleneglycol dimethacrylate, triethyleneglycol dimethacrylate, diethyleneglycol dimethacrylate, ethyleneglycol dimethacrylate, tetraethyleneglycol divinyl ether, triethyleneglycol divinyl ether, diethyleneglycol divinyl ether, ethyleneglycol divinyl ether, trimethylopropane tri methacrylate, pentaerythritol tetramethacrylate, bisphenol A dimethacrylate, vinyl methacrylate, ethylenediamine dimethyacrylamide, ethylenediamine diacrylamide, glycerol dimethacrylate, triallyl isocyanurate, triallyl cyanurate, allylmethacrylate, allylacrylate, N-allyl-methacrylamide, N-allyl-acrylamide, 1,3-bis(methacrylamidopropyl)-1,1,3,3-tetrakis(trimethyl-siloxy)disiloxane, N, N′-methylenebisacrylamide, N,N′-methylenebismethacrylamide, N,N′-ethylenebisacrylamide, N,N′-ethylenebismethacrylamide, 1,3-bis(N-methacrylamidopropyl)-1,1,3,3-tetrakis-(trimethylsiloxy)disiloxane, 1,3-bis(methacrylamidobutyl)-1,1,3,3-tetrakis(trimethylsiloxy)-disiloxane, 1,3-bis(acrylamidopropyl)-1,1,3,3-tetrakis(trimethylsiloxy)-disiloxane, 1,3-bis(methacryloxyethylureidopropyl)-1,1,3,3-tetrakis(trimethylsiloxy)disiloxane, and combinations thereof. A preferred cross-linking agent is di-(meth)acrylate-terminated polyethylene glycol, di-(meth)acrylate-terminated polyoxyethylene-polyoxypropylene block copolymer, tetra(ethyleneglycol) diacrylate, tri(ethyleneglycol) diacrylate, ethyleneglycol diacrylate, di(ethyleneglycol) diacrylate, methylenebisacrylamide, triallyl isocyanurate, allyl (meth)acrylate, or triallyl cyanurate. The amount of a cross-linking agent used is expressed in the weight content with respect to the total polymer and is preferably in the range from about 0.05% to about 3% (more preferably from about 0.1% to about 2%).

Any suitable UV-absorbing vinylic monomers can be used in a polymerizable composition for preparing a polymer of the invention. Examples of preferred UV-absorbing and UV/HEVL-absorbing, benzotriazole-containing vinylic monomers include without limitation: 2-(2-hydroxy-5-vinylphenyl)-2H-benzotriazole, 2-(2-hydroxy-5-acrylyloxyphenyl)-2H-benzotriazole, 2-(2-hydroxy-3-methacrylamido methyl-5-tert octylphenyl) benzotriazole, 2-(2′-hydroxy-5′-methacrylamidophenyl)-5-chlorobenzotriazole, 2-(2′-hydroxy-5′-methacrylamidophenyl)-5-methoxybenzotriazole, 2-(2′-hydroxy-5′-methacryloxypropyl-3′-t-butyl-phenyl)-5-chlorobenzotriazole, 2-(2′-hydroxy-5′-methacryloxypropylphenyl) benzotriazole, 2-hydroxy-5-methoxy-3-(5-(trifluoromethyl)-2H-benzo[d][1,2,3]triazol-2-yl)benzyl methacrylate (WL-1), 2-hydroxy-5-methoxy-3-(5-methoxy-2H-benzo[d][1,2,3]triazol-2-yl)benzyl methacrylate (WL-5), 3-(5-fluoro-2H-benzo[d][1,2,3]triazol-2-yl)-2-hydroxy-5-methoxybenzyl methacrylate (WL-2), 3-(2H-benzo[d][1,2,3]triazol-2-yl)-2-hydroxy-5-methoxybenzyl methacrylate (WL-3), 3-(5-chloro-2H-benzo[d][1,2,3]triazol-2-yl)-2-hydroxy-5-methoxybenzyl methacrylate (WL-4), 2-hydroxy-5-methoxy-3-(5-methyl-2H-benzo[d][1,2,3]triazol-2-yl)benzyl methacrylate (WL-6), 2-hydroxy-5-methyl-3-(5-(trifluoromethyl)-2H-benzo[d][1,2,3]triazol-2-yl)benzyl methacrylate (WL-7), 4-allyl-2-(5-chloro-2H-benzo[d][1,2,3]triazol-2-yl)-6-methoxyphenol (WL-8), 2-{2′-Hydroxy-3′-tert-5-[3″-(4″-vinylbenzyloxy)propoxy]phenyl}-5-methoxy-2H-benzotriazole, phenol, 2-(5-chloro-2H-benzotriazol-2-yl)-6-(1,1-dimethylethyl)-4-ethenyl-(UVAM), 2-(2′-hydroxy-5′-methacryloxyethylphenyl) benzotriazole (2-Propenoic acid, 2-methyl-, 2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl ester, Norbloc), 2-{2′-Hydroxy-3′-tert-butyl-5′-[3′-methacryloyloxypropoxy]phenyl}-5-chloro-2H-benzotriazole (UV28), 2-{2′-Hydroxy-3′-tert-butyl-5′-[3′-methacryloyloxypropoxy]phenyl}-5-methoxy-2H-benzotriazole (UV13), 2-[2′-Hydroxy-3′-tert-butyl-5′-(3′-acryloyloxypropoxy)phenyl]-5-trifluoromethyl-2H-benzotriazole (CF₃-UV13), 2-(2′-hydroxy-5-methacrylamidophenyl)-5-methoxybenzotriazole (UV6), 2-(3-allyl-2-hydroxy-5-methylphenyl)-2H-benzotriazole (UV9), 2-(2-Hydroxy-3-methallyl-5-methylphenyl)-2H-benzotriazole (UV12), 2-3′-t-butyl-2′-hydroxy-5′-(3″-dimethylvinylsilylpropoxy)-2′-hydroxy-phenyl)-5-methoxybenzotriazole (UV15), 2-(2′-hydroxy-5′-methacryloylpropyl-3′-tert-butyl-phenyl)-5-methoxy-2H-benzotriazole (UV16), 2-(2′-hydroxy-5′-acryloylpropyl-3′-tert-butyl-phenyl)-5-methoxy-2H-benzotriazole (UV16A), 2-Methylacrylic acid 3-[3-tert-butyl-5-(5-chlorobenzotriazol-2-yl)-4-hydroxyphenyl]-propyl ester (16-100, CAS#96478-15-8), 2-(3-(tert-butyl)-4-hydroxy-5-(5-methoxy-2H-benzo[d][1,2,3]triazol-2-yl)phenoxy)ethyl methacrylate (16-102); Phenol, 2-(5-chloro-2H-benzotriazol-2-yl)-6-methoxy-4-(2-propen-1-yl) (CAS#1260141-20-5); 2-[2-Hydroxy-5-[3-(methacryloyloxy)propyl]-3-tert-butylphenyl]-5-chloro-2H-benzotriazole; Phenol, 2-(5-ethenyl-2H-benzotriazol-2-yl)-4-methyl-, homopolymer (901) (CAS#83063-87-0). In accordance with the invention, the polymerizable composition comprises about 0.2% to about 5.0%, preferably about 0.3% to about 2.5%, more preferably about 0.5% to about 1.8%, by weight of a UV-absorbing agent.

Examples of suitable thermal initiators include, but are not limited to, 2,2′-azobis (2,4-dimethylpentanenitrile), 2,2′-azobis (2-methylpropanenitrile), 2,2′-azobis (2-methylbutanenitrile), peroxides such as benzoyl peroxide, and the like. Preferably, the thermal initiator is 2,2′-azobis(isobutyronitrile) (AIBN).

Suitable photoinitiators are benzoin methyl ether, diethoxyacetophenone, a benzoylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone and Darocur and Irgacur types, preferably Darocur 1173® and Darocur 2959®, Germanium-based Norrish Type I photoinitiators. Examples of benzoylphosphine initiators include 2,4,6-trimethylbenzoyldiphenylophosphine oxide; bis-(2,6-dichlorobenzoyl)-4-N-propylphenylphosphine oxide; and bis-(2,6-dichlorobenzoyl)-4-N-butylphenylphosphine oxide. Reactive photoinitiators which can be incorporated, for example, into a macromer or can be used as a special monomer are also suitable. Examples of reactive photoinitiators are those disclosed in EP 632 329. The polymerization can then be triggered off by actinic radiation, for example light, in particular UV light of a suitable wavelength. The spectral requirements can be controlled accordingly, if appropriate, by addition of suitable photosensitizers.

Where a vinylic monomer capable of absorbing ultra-violet radiation and high energy violet light (HEVL) is used in the invention, a Germanium-based Norrish Type I photoinitiator and a light source including a light in the region of about 400 to about 550 nm are preferably used to initiate a free-radical polymerization. Any Germane-based Norrish Type I photoinitiators can be used in this invention, so long as they are capable of initiating a free-radical polymerization under irradiation with a light source including a light in the region of about 400 to about 550 nm. Examples of Germanium-based Norrish Type I photoinitiators are acylgermanium compounds described in U.S. Pat. No. 7,605,190. Preferably, the monomer of lens-forming materials comprises at least one of the following acylgermanium compounds.

The bioactive agent is any compound that can prevent a malady in the eye or reduce the symptoms of an eye malady. The bioactive agent can be a drug, an amino acid (e.g., taurine, glycine, etc.), a polypeptide, a protein, a nucleic acid, or any combination thereof. Examples of drugs useful herein include, but are not limited to, rebamipide, ketotifen, olaptidine, cromoglycolate, cyclosporine, nedocromil, levocabastine, lodoxamide, ketotifen, or the pharmaceutically acceptable salt or ester thereof. Other examples of bioactive agents include 2-pyrrolidone-5-carboxylic acid (PCA), alpha hydroxyl acids (e.g., glycolic, lactic, malic, tartaric, mandelic and citric acids and salts thereof, etc.), linoleic and gamma linoleic acids, and vitamins (e.g., B5, A, B6, etc.).

Examples of leachable lubricants include without limitation mucin-like materials (e.g., polyglycolic acid) and non-crosslinkable hydrophilic polymers (i.e., without ethylenically unsaturated groups). Any hydrophilic polymers or copolymers without any ethylenically unsaturated groups can be used as leachable lubricants. Preferred examples of non-crosslinkable hydrophilic polymers include, but are not limited to, polyvinyl alcohols (PVAs), polyamides, polyimides, polylactone, a homopolymer of a vinyl lactam, a copolymer of at least one vinyl lactam in the presence or in the absence of one or more hydrophilic vinylic comonomers, a homopolymer of acrylamide or methacrylamide, a copolymer of acrylamide or methacrylamide with one or more hydrophilic vinylic monomers, polyethylene oxide (i.e., polyethylene glycol (PEG)), a polyoxyethylene derivative, poly-N—N-dimethylacrylamide, polyacrylic acid, poly 2 ethyl oxazoline, heparin polysaccharides, polysaccharides, and mixtures thereof. The weight-average molecular weight M_(w) of the non-crosslinkable hydrophilic polymer is preferably from 5,000 to 1,00,000.

Examples of leachable tear-stabilizing agents include, without limitation, phospholipids, monoglycerides, diglycerides, triglycerides, glycolipids, glyceroglycolipids, sphingolipids, sphingo-glycolipids, fatty alcohols, fatty acids, mineral oils, and mixtures thereof. Preferably, a tear stabilizing agent is a phospholipid, a monoglyceride, a diglyceride, a triglyceride, a glycolipid, a glyceroglycolipid, a sphingolipid, a sphingo-glycolipid, a fatty acid having 8 to 36 carbon atoms, a fatty alcohol having 8 to 36 carbon atoms, or a mixture thereof.

In accordance with the invention, a polymerizable composition can be a solution or a melt at a temperature from about 20° C. to about 85° C. Preferably, a polymerizable composition is a solution of all desirable components in a suitable solvent, or a mixture of suitable solvents.

A polymerizable composition can be prepared by dissolving all of the desirable components in any suitable solvent, such as, water, a mixture of water and one or more organic solvents miscible with water, an organic solvent, or a mixture of one or more organic solvents, as known to a person skilled in the art.

Example of preferred organic solvents includes without limitation, tetrahydrofuran, tripropylene glycol methyl ether, dipropylene glycol methyl ether, ethylene glycol n-butyl ether, ketones (e.g., acetone, methyl ethyl ketone, etc.), diethylene glycol n-butyl ether, diethylene glycol methyl ether, ethylene glycol phenyl ether, propylene glycol methyl ether, propylene glycol methyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol n-propyl ether, dipropylene glycol n-propyl ether, tripropylene glycol n-butyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether, propylene glycol phenyl ether dipropylene glycol dimethyl ether, polyethylene glycols, polypropylene glycols, ethyl acetate, butyl acetate, amyl acetate, methyl lactate, ethyl lactate, i-propyl lactate, methylene chloride, 2-butanol, 1-propanol, 2-propanol, menthol, cyclohexanol, cyclopentanol and exonorborneol, 2-pentanol, 3-pentanol, 2-hexanol, 3-hexanol, 3-methyl-2-butanol, 2-heptanol, 2-octanol, 2-nonanol, 2-decanol, 3-octanol, norborneol, tert-butanol, tert-amyl alcohol, 2-methyl-2-pentanol, 2,3-dimethyl-2-butanol, 3-methyl-3-pentanol, 1-methylcyclohexanol, 2-methyl-2-hexanol, 3,7-dimethyl-3-octanol, 1-chloro-2-methyl-2-propanol, 2-methyl-2-heptanol, 2-methyl-2-octanol, 2-2-methyl-2-nonanol, 2-methyl-2-decanol, 3-methyl-3-hexanol, 3-methyl-3-heptanol, 4-methyl-4-heptanol, 3-methyl-3-octanol, 4-methyl-4-octanol, 3-methyl-3-nonanol, 4-methyl-4-nonanol, 3-methyl-3-octanol, 3-ethyl-3-hexanol, 3-methyl-3-heptanol, 4-ethyl-4-heptanol, 4-propyl-4-heptanol, 4-isopropyl-4-heptanol, 2,4-dimethyl-2-pentanol, 1-methylcyclopentanol, 1-ethylcyclopentanol, 1-ethylcyclopentanol, 3-hydroxy-3-methyl-1-butene, 4-hydroxy-4-methyl-1-cyclopentanol, 2-phenyl-2-propanol, 2-methoxy-2-methyl-2-propanol 2,3,4-trimethyl-3-pentanol, 3,7-dimethyl-3-octanol, 2-phenyl-2-butanol, 2-methyl-1-phenyl-2-propanol and 3-ethyl-3-pentanol, 1-ethoxy-2-propanol, 1-methyl-2-propanol, t-amyl alcohol, isopropanol, 1-methyl-2-pyrrolidone, N,N-dimethylpropionamide, dimethyl formamide, dimethyl acetamide, dimethyl propionamide, N-methyl pyrrolidinone, and mixtures thereof.

Lens molds for making contact lenses are well known to a person skilled in the art and, for example, are employed in cast molding or spin casting. For example, a mold (for cast molding) generally comprises at least two mold sections (or portions) or mold halves, i.e. first and second mold halves. The first mold half defines a first molding (or optical) surface and the second mold half defines a second molding (or optical) surface. The first and second mold halves are configured to receive each other such that a lens forming cavity is formed between the first molding surface and the second molding surface. The molding surface of a mold half is the cavity-forming surface of the mold and in direct contact with lens-forming material.

Methods of manufacturing mold sections for cast-molding a contact lens are generally well known to those of ordinary skill in the art. The process of the present invention is not limited to any particular method of forming a mold. In fact, any method of forming a mold can be used in the present invention. The first and second mold halves can be formed through various techniques, such as injection molding or lathing. Examples of suitable processes for forming the mold halves are disclosed in U.S. Pat. No. 4,444,711 to Schad; U.S. Pat. No. 4,460,534 to Boehm et al.; U.S. Pat. No. 5,843,346 to Morrill; and U.S. Pat. No. 5,894,002 to Boneberger et al.

Virtually all materials known in the art for making molds can be used to make molds for making contact lenses. For example, polymeric materials, such as polyethylene, polypropylene, polystyrene, PMMA, Topas® COC grade 8007-S10 (clear amorphous copolymer of ethylene and norbornene, from Ticona GmbH of Frankfurt, Germany and Summit, N.J.), or the like can be used. Other materials that allow UV light transmission could be used, such as quartz glass and sapphire.

In a preferred embodiment, reusable molds are used and the silicone-hydrogel lens-forming composition is cured actinically under a spatial limitation of actinic radiation to form a SiHy contact lens. Examples of preferred reusable molds are those disclosed in U.S. patent application Ser. No. 08/274,942 filed Jul. 14, 1994, Ser. No. 10/732,566 filed Dec. 10, 2003, Ser. No. 10/721,913 filed Nov. 25, 2003, and U.S. Pat. No. 6,627,124. Reusable molds can be made of quartz, glass, sapphire, CaF₂, a cyclic olefin copolymer (such as for example, Topas® COC grade 8007-S10 (clear amorphous copolymer of ethylene and norbornene) from Ticona GmbH of Frankfurt, Germany and Summit, N.J., Zeonex® and Zeonor® from Zeon Chemicals LP, Louisville, Ky.), polymethylmethacrylate (PMMA), polyoxymethylene from DuPont (Delrin), Ultem® (polyetherimide) from G.E. Plastics, PrimoSpire®, etc.

In accordance with the invention, the polymerizable composition can be introduced (dispensed) into a cavity formed by a mold according to any known methods.

After the polymerizable composition is dispensed into the mold, it is polymerized to produce a contact lens. Crosslinking may be initiated thermally or actinically, preferably by exposing the lens-forming composition in the mold to a spatial limitation of actinic radiation to crosslink the polymerizable components in the polymerizable composition.

Opening of the mold so that the molded article can be removed from the mold may take place in a manner known per se.

The molded contact lens can be subject to lens extraction to remove unpolymerized polymerizable components. The extraction solvent can be any solvent known to a person skilled in the art. Examples of suitable extraction solvent are those described above.

In accordance with the invention, the silicone hydrogel contact lens is placed in contact with an organic solvent-based solution of polymethacrylic acid for a time period of from about 30 seconds to about 120 seconds (preferably from about 35 second to about 100 seconds, more preferably from about 40 seconds to about 80 seconds) to form a base coating.

Contacting of a contact lens with a coating solution of a polymer can occur by dipping it into the coating solution or by spraying it with the coating solution. One contacting process involves solely dipping the contact lens in a bath of a coating solution for a period of time or alternatively dipping the contact lens sequentially in a series of bath of coating solutions for a fixed shorter time period for each bath. Another contacting process involves solely spray a coating solution. However, a number of alternatives involve various combinations of spraying- and dipping-steps may be designed by a person having ordinary skill in the art.

In accordance with the invention, the weight average molecular weight M_(w) of polymethacrylic acid for forming a base coating on silicone hydrogel contact lenses is at least about 10,000 Daltons, preferably at least about 50,000 Daltons, more preferably from about 100,000 Daltons to about 1,000,000 Daltons. The concentration of PMAA solution is from about 0.001% to about 1.5%, preferably from about 0.002% to about 0.75%, more preferably from 0.003% to about 0.1% by weight relative to the total weight of the organic-based solution. A solution of PMAA for forming a base coating on contact lenses can be prepared by dissolving PMAA in a solvent system comprising at least about 60% by weight of an organic solvent, preferably in an organic solvent or a mixture of one or more organic solvent. It is believed that a solvent system containing at least about 60% by weight of an organic solvent, or preferably an organic solvent or a mixture organic solvents, can swell a silicone hydrogel contact lens so that a portion of PMAA may penetrate into the silicone hydrogel contact lens and increase the durability of the base coating.

Polymethacrylic acid is selected as a base coating material in the invention for decreasing the coating's susceptibility to deposition and accumulation of positively-charged antimicrobials in a lens care solution. PMAA has a hydrogen dissociation constant pKa of about 5.3, higher than PAA's pa of about 4.0 (see, H. Dong, J. Phys. Chem. A 112 (49): 12687-12694 (2008); F. Mitsuko, R. Grubbs, and J. D. Baldeschwieler, J. Colloid Interface Sci. 185: 210-216 (1997); S. J. Grainger and E. H. EI-Sayed, in Biologically-Responsive Hybrid Biomaterials: A Reference for Material Scientists and Bioengineers, E. Jabbari et A. Khademhosseini, Eds., Boston, Mass.: Artech Publishing (2010), Chapter 7, pp 171-190). Because of the differences in pKa, the ionization degrees of the carboxyl groups of PMAA and PAA at neutral pH (around 7.0) can be significantly different and can have different levels of uptake of positively-charged antimicrobial agents (e.g., PHMB, aldox, POLYQUAD, etc.) present in lens care solutions, even at identical concentrations of carboxyl groups.

The thickness of PMAA base coating can be adjusted by increasing the PMAA concentration or increasing the contacting time of the silicone hydrogel contact lens with the PMAA solution or both. In a preferred embodiment, the PMAA base coating has a concentration of carboxyl groups of about 20 nanomoles per lens or less, preferably about 17.5 nanomoles per lens or less, more preferably about 15 nanomoles per lens or less, as determined according to the staining essay described in the examples or described in US20140356965A1.

In order to further decrease the uptakes of positively-charged antimicrobial agents (e.g., PHMB, aldox, POLYQUAD, etc.) present in lens care solutions, it would be desirable to reduce the thickness of the PMAA base coating, i.e., the concentration of carboxyl groups in the base coating of the silicone hydrogel contact lens. However, if the thickness of PMAA base coating is too thin (or the concentration of carboxyl groups in the base coating is too), such a base coating cannot not be used as stable anchor for a non-silicone hydrogel coating which is formed by covalently attaching a hydrophilic polymeric material onto the PMAA base coating. It is discovered that by contacting the PMAA base coating with a solution of polyamidoamine epichlorohydrin (PAE) at a pH from about 2.0 to about 3.5, a PAE-doped base coating can be formed for subsequent formation of a relatively-durable non-silicone hydrogel coating on the silicone hydrogel contact lens. It is believed that at a pH of from about 2.0 to about 3.5 PAE may intermingle and interact with PMAA in the base coating through the hydrogen bonding interactions. Upon heating in the presence of a water-soluble thermally crosslinkable hydrophilic polymeric material having azetidinium groups and carboxyl or amino groups in a solution, crosslinkages can be formed between a portion of the carboxyl groups of PMAA and a portion of the azetidinium groups of PAE in the PAE-doped base coating on the silicone hydrogel contact lens according to thermally-induced reaction mechanism involving an azetidinium group and a carboxyl group (or primary amino or secondary amino group) shown in Scheme I

in which X₁ is —S—*, —OC(═O)—*, or —NR′—* in which R′ is hydrogen or a C₁-C₂₀ unsubstituted or substituted alkyl group, and * represents an organic radical. Because of the partial penetrations of both PMAA and PAE, interlocks may be formed between the polymer networks of the silicone hydrogel contact lens and the polymer networks of the crosslinked base coating, thereby stabilizing the crosslinked base coating. The remaining portion of azetidinium and carboxyl groups of the crosslinked base coating can react with the carboxyl or amino groups and azetidinium groups of the hydrophilic polymeric material to form the relatively-durable non-silicone hydrogel coating on the silicone hydrogel contact lens.

It is found that after the PAE-doped base coating of a silicone hydrogel contact lens is crosslinked by heating in the absence of a water-soluble thermally-crosslinkable hydrophilic polymeric material having azetidinium groups and amino or carboxyl groups in a solution, the crosslinked base coating cannot be served as an anchor layer to form a lubricious hydrogel coating even upon heating again in the presence of according to thermally-induced reaction mechanism involving an azetidinium group and a carboxyl, primary amino or secondary amino group as shown below. Therefore, according to the invention, a silicone hydrogel contact lens with a PAE-doped base coating thereon should be heated only in the presence of a water-soluble thermally-crosslinkable hydrophilic polymeric material having azetidinium groups and optionally (but preferably) amino or carboxyl groups in a solution, crosslinking the base coating simultaneously covalently attaching the hydrophilic polymeric material onto the base coating.

Contacting of a contact lens having a base coating thereon with a PAE solution can occur by dipping it into the PAE solution or by spraying it with the PAE solution. One contacting process involves solely dipping the contact lens in a bath of a PAE solution for a period of time or alternatively dipping the contact lens sequentially in a series of bath of PAE solutions for a fixed shorter time period for each bath. Another contacting process involves solely spray a PAE solution. However, a number of alternatives involve various combinations of spraying- and dipping-steps may be designed by a person having ordinary skill in the art. The silicone hydrogel contact lens is placed in contact with the PAE solution for a time period of from about 30 seconds to about 300 seconds (preferably from about 35 second to about 200 seconds, more preferably from about 40 seconds to about 120 seconds) to form a PAE-doped base coating. The weight average molecular weight M_(w) of polyamidoamine-epichlorohydrin is at least about 10,000 Daltons, preferably at least about 50,000 Daltons, more preferably from about 100,000 Daltons to about 5,000,000 Daltons. The concentration of PAE solution is from about 0.001% to about 5%, preferably from about 0.01% to about 2.5%, more preferably from 0.1% to about 1.5% by weight relative to the total weight of the PAE solution. A PAE solution can be prepared by dissolving polyamidoamine-epichlorohydrin in water or a mixture of water and one or more organic solvents.

In a preferred embodiment, the step of heating can be carried out conveniently and directly in a lens package during autoclave (i.e., heating the lens package with the lens in a packaging solution about 115° C. to about 125° C. for at least about 20 minutes, preferably from 20 to 60 minutes under pressure) which is a commonly-used sterilization process in the contact lens industry. Any azetidinium groups which are not reacted with carboxyl, primary amino or secondary amino groups will be hydrolyzed during autoclave as shown below

In accordance with the invention, a water-soluble and thermally-crosslinkable hydrophilic polymeric material having azetidinium groups and optionally (but preferably) amino or carboxyl groups can be a poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin or a chemically-modified poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin, a chemically-modified polyamidoamine-epichlorohydrin, or combinations thereof. Preferably, a water-soluble and thermally-crosslinkable hydrophilic polymeric material having azetidinium groups and optionally (but preferably) amino or carboxyl groups is a chemically-modified poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin or a chemically-modified polyamidoamine-epichlorohydrin, which comprises (i) from about 20% to about 95% by weight of first polymer chains derived from a polyamidoamine-epichlorohydrin or a poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin, (ii) from about 5% to about 80% by weight of hydrophilic moieties or second polymer chains derived from at least one hydrophilicity-enhancing agent having at least one reactive functional group selected from the group consisting of amino group, carboxyl group, thiol group, and combination thereof, wherein the hydrophilic moieties or second polymer chains are covalently attached to the first polymer chains through one or more covalent linkages each formed between one azetidinium group of the polyamidoamine-epichlorohydrin or the poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin and one amino, carboxyl or thiol group of the hydrophilicity-enhancing agent, and (iii) azetidinium groups which are parts of the first polymer chains or pendant or terminal groups covalently attached to the first polymer chains. The composition of the hydrophilic polymeric material is determined by the composition (based on the total weight of the reactants) of a reactants mixture used for preparing the thermally-crosslinkable hydrophilic polymeric material according to the crosslinking reactions shown in Scheme I above. For example, if a reactant mixture comprises about 75% by weight of a polyamidoamine-epichlorohydrin and about 25% by weight of at least one hydrophilicity-enhancing agent based on the total weight of the reactants, then the resultant hydrophilic polymeric material comprise about 75% by weight of first polymer chains derived from the polyamidoamine-epichlorohydrin and about 25% by weight of hydrophilic moieties or second polymer chains derived from said at least one hydrophilicity-enhancing agent. The azetidinium groups of the thermally-crosslinkable hydrophilic polymeric material are those azetidinium groups (of the polyamidoamine-epichlorohydrin) which do not participate in crosslinking reactions for preparing the thermally-crosslinkable hydrophilic polymeric material.

Any suitable hydrophilicity-enhancing agents can be used in the invention so long as they contain at least one amino group, at least one carboxyl group, and/or at least one thiol group.

A preferred class of hydrophilicity-enhancing agents include without limitation: primary amino-, secondary amino-, carboxyl- or thiol-containing monosaccharides (e.g., 3-amino-1,2-propanediol, 1-thiolglycerol, 5-keto-D-gluconic acid, galactosamine, glucosamine, galacturonic acid, gluconic acid, glucosaminic acid, mannosamine, saccharic acid 1,4-lactone, saccharide acid, Ketodeoxynonulosonic acid, N-methyl-D-glucamine, 1-amino-1-deoxy-β-D-galactose, 1-amino-1-deoxysorbitol, 1-methylamino-1-deoxysorbitol, N-aminoethyl gluconamide); primary amino-, secondary amino-, carboxyl- or thiol-containing disaccharides (e.g., chondroitin disaccharide sodium salt, di(β-D-xylopyranosyl)amine, digalacturonic acid, heparin disaccharide, hyaluronic acid disaccharide, Lactobionic acid); and primary amino-, secondary amino-, carboxyl- or thiol-containing oligosaccharides (e.g., carboxymethyl-β-cyclodextrin sodium salt, trigalacturonic acid); and combinations thereof.

Another preferred class of hydrophilicity-enhancing agents is hydrophilic polymers having one or more (primary or secondary) amino, carboxyl and/or thiol groups. More preferably, the content of the amino (—NHR′ with R′ as defined above), carboxyl (—COOH) and/or thiol (—SH) groups in a hydrophilic polymer as a hydrophilicity-enhancing agent is less than about 40%, preferably less than about 30%, more preferably less than about 20%, even more preferably less than about 10%, by weight based on the total weight of the hydrophilic polymer.

One preferred class of hydrophilic polymers as hydrophilicity-enhancing agents are (primary or secondary) amino- or carboxyl-containing polysaccharides, for example, such as, carboxymethylcellulose (having a carboxyl content of about 40% or less, which is estimated based on the composition of repeating units, —[C₆H_(10-m)O₅(CH₂CO₂H)_(m)]— in which m is 1 to 3), carboxyethylcellulose (having a carboxyl content of about 36% or less, which is estimated based on the composition of repeating units, —[C₆H_(10-m)O₅(C₂H₄CO₂H)_(m)]— in which m is 1 to 3) carboxypropylcellulose (having a carboxyl content of about 32% or less, which is estimated based on the composition of repeating units, —[C₆H_(10-m)O₅(C₃H₆CO₂H)_(m)]—, in which m is 1 to 3), hyaluronic acid (having a carboxyl content of about 11%, which is estimated based on the composition of repeating units, —(C₁₃H₂₀O₉NCO₂H)—), chondroitin sulfate (having a carboxyl content of about 9.8%, which is estimated based on the composition of repeating units, —(C₁₂H₁₈O₁₃NS CO₂H)—), or combinations thereof.

Another preferred class of hydrophilic polymers as hydrophilicity-enhancing agents include without limitation: poly(ethylene glycol) (PEG) with mono-amino (primary or secondary amino), carboxyl or thiol group (e.g., PEG-NH₂, PEG-SH, PEG-COOH); H₂N-PEG-NH₂; HOOC-PEG-COOH; HS-PEG-SH; H₂N-PEG-COOH; HOOC-PEG-SH; H₂N-PEG-SH; multi-arm PEG with one or more amino (primary or secondary), carboxyl or thiol groups; PEG dendrimers with one or more amino (primary or secondary), carboxyl or thiol groups; a diamino-(primary or secondary) or dicarboxyl-terminated homo- or co-polymer of a non-reactive hydrophilic vinylic monomer; a monoamino- (primary or secondary) or monocarboxyl-terminated homo- or co-polymer of a non-reactive hydrophilic vinylic monomer; a copolymer which is a polymerization product of a composition comprising (1) about 60% by weight or less, preferably from about 0.1% to about 30%, more preferably from about 0.5% to about 20%, even more preferably from about 1% to about 15%, by weight of one or more reactive vinylic monomers and (2) at least one non-reactive hydrophilic vinylic monomer; and combinations thereof. Reactive vinylic monomer(s) and non-reactive hydrophilic vinylic monomer(s) are those described previously.

More preferably, a hydrophilic polymer as a hydrophilicity-enhancing agent is PEG-NH₂; PEG-SH; PEG-COOH; H₂N-PEG-NH₂; HOOC-PEG-COOH; HS-PEG-SH; H₂N-PEG-COOH; HOOC-PEG-SH; H₂N-PEG-SH; multi-arm PEG with one or more amino, carboxyl or thiol groups; PEG dendrimers with one or more amino, carboxyl or thiol groups; a monoamino-, monocarboxyl-, diamino- or dicarboxyl-terminated homo- or copolymer of a non-reactive hydrophilic vinylic monomer selected from the group consisting of acrylamide (AAm), N,N-dimethylacrylamide (DMA), N-vinylpyrrolidone (NVP), N-vinyl-N-methyl acetamide, glycerol (meth)acrylate, hydroxyethyl (meth)acrylate, N-hydroxyethyl (meth)acrylamide, C₁-C₄-alkoxy polyethylene glycol (meth)acrylate having a weight average molecular weight of up to 400 Daltons, vinyl alcohol, N-methyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone, 5-methyl-3-methylene-2-pyrrolidone, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (metha)crylamide, (meth)acryloyloxyethyl phosphorylcholine, and combinations thereof; a copolymer which is a polymerization product of a composition comprising (1) from about 0.1% to about 30%, preferably from about 0.5% to about 20%, more preferably from about 1% to about 15%, by weight of acrylic acid, C₁-C₃ alkylacrylic acid, allylamine and/or amino-C₂-C₄ alkyl (meth)acrylate, and (2) at least one non-reactive hydrophilic vinylic monomer selected from the group consisting of acryamide, N,N-dimethylacrylamide, N-vinyl pyrrolidone, (meth)acryloyloxyethyl phosphorylcholine, N-vinyl-N-methyl acetamide, glycerol (meth)acrylate, hydroxyethyl (meth)acrylate, N-hydroxyethyl (meth)acrylamide, C₁-C₄-alkoxy polyethylene glycol (meth)acrylate having a weight average molecular weight of up to 400 Daltons, vinyl alcohol, and combination thereof.

Most preferably, the hydrophilicity-enhancing agent as a hydrophilicity-enhancing agent is PEG-NH₂; PEG-SH; PEG-COOH; monoamino-, monocarboxyl-, diamino- or dicarboxyl-terminated polyvinylpyrrolidone; monoamino-, monocarboxyl-, diamino- or dicarboxyl-terminated polyacrylamide; monoamino-, monocarboxyl-, diamino- or dicarboxyl-terminated poly(DMA); monoamino- or monocarboxyl-, diamino- or dicarboxyl-terminated poly(DMA-co-NVP); monoamino-, monocarboxyl-, diamino- or dicarboxyl-terminated poly(NVP-co-N,N-dimethylaminoethyl (meth)acrylate)); monoamino-, monocarboxyl-, diamino- or dicarboxyl-terminated poly(vinylalcohol); monoamino-, monocarboxyl-, diamino- or dicarboxyl-terminated poly[(meth)acryloyloxyethyl phosphrylcholine] homopolymer or copolymer; monoamino-, monocarboxyl-, diamino- or dicarboxyl-terminated poly(NVP-co-vinyl alcohol); monoamino-, monocarboxyl-, diamino- or dicarboxyl-terminated poly(DMA-co-vinyl alcohol); poly[(meth)acrylic acid-co-acrylamide] with from about 0.1% to about 30%, preferably from about 0.5% to about 20%, more preferably from about 1% to about 15%, by weight of (meth)acrylic acid; poly[(meth)acrylic acid-co-NVP) with from about 0.1% to about 30%, preferably from about 0.5% to about 20%, more preferably from about 1% to about 15%, by weight of (meth)acrylic acid; a copolymer which is a polymerization product of a composition comprising (1) (meth)acryloyloxyethyl phosphorylcholine and (2) from about 0.1% to about 30%, preferably from about 0.5% to about 20%, more preferably from about 1% to about 15%, by weight of acrylic acid, C₁-C₃ alkylacrylic acid, allylamine and/or amino-C₂-C₄alkyl (meth)acrylate; and combination thereof.

PEGs with functional groups and multi-arm PEGs with functional groups can be obtained from various commercial suppliers, e.g., Polyscience, and Shearwater Polymers, inc., etc.

Monoamino-, monocarboxyl-, diamino- or dicarboxyl-terminated homo- or copolymers of one or more non-reactive hydrophilic vinylic monomers or of a phosphorylcholine-containing vinylic monomer can be prepared according to procedures described in U.S. Pat. No. 6,218,508. For example, to prepare a diamino- or dicarboxyl-terminated homo- or co-polymer of a non-reactive hydrophilic vinylic monomer, the non-reactive vinylic monomer, a chain transfer agent with an amino or carboxyl group (e.g., 2-aminoethanethiol, 2-mercaptopropinic acid, thioglycolic acid, thiolactic acid, or other hydroxymercaptanes, aminomercaptans, or carboxyl-containing mercaptanes) and optionally other vinylic monomer are copolymerized (thermally or actinically) with a reactive vinylic monomer (having an amino or carboxyl group), in the presence of an free-radical initiator. Generally, the molar ratio of chain transfer agent to that of all of vinylic monomers other than the reactive vinylic monomer is from about 1:5 to about 1:100, whereas the molar ratio of chain transfer agent to the reactive vinylic monomer is 1:1. In such preparation, the chain transfer agent with amino or carboxyl group is used to control the molecular weight of the resultant hydrophilic polymer and forms a terminal end of the resultant hydrophilic polymer so as to provide the resultant hydrophilic polymer with one terminal amino or carboxyl group, while the reactive vinylic monomer provides the other terminal carboxyl or amino group to the resultant hydrophilic polymer. Similarly, to prepare a monoamino- or monocarboxyl-terminated homo- or co-polymer of a non-reactive hydrophilic vinylic monomer, the non-reactive vinylic monomer, a chain transfer agent with an amino or carboxyl group (e.g., 2-aminoethanethiol, 2-mercaptopropinic acid, thioglycolic acid, thiolactic acid, or other hydroxymercaptanes, aminomercaptans, or carboxyl-containing mercaptanes) and optionally other vinylic monomers are copolymerized (thermally or actinically) in the absence of any reactive vinylic monomer.

As used herein, a copolymer of a non-reactive hydrophilic vinylic monomer refers to a polymerization product of a non-reactive hydrophilic vinylic monomer with one or more additional vinylic monomers. Copolymers comprising a non-reactive hydrophilic vinylic monomer and a reactive vinylic monomer (e.g., a carboxyl-containing vinylic monomer, a primary amino group-containing vinylic monomer or a secondary amino group-containing vinylic monomer) can be prepared according to any well-known radical polymerization methods or obtained from commercial suppliers. Copolymers containing methacryloyloxyethyl phosphorylcholine and carboxyl-containing vinylic monomer (or amino-containing vinylic monomer) can be obtained from NOF Corporation (e.g., LIPIDURE®-A and -AF).

The weight average molecular weight M_(w) of the hydrophilic polymer having at least one amino, carboxyl or thiol group (as a hydrophilicity-enhancing agent) is preferably from about 500 to about 1,000,000, more preferably from about 1,000 to about 500,000, even more preferably from about 5,000 to about 250,000 Daltons.

In accordance with the invention, the reaction between a hydrophilicity-enhancing agent and a poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin copolymer (or a polyamidoamine-epichlorohydrin) is carried out at a temperature of from about 40° C. to about 80° C. for a period of time sufficient (from about 0.3 hour to about 24 hours, preferably from about 1 hour to about 12 hours, even more preferably from about 2 hours to about 8 hours) to form a water-soluble and thermally-crosslinkable hydrophilic polymeric material containing azetidinium groups.

In accordance with the invention, the concentration of a hydrophilicity-enhancing agent relative to a poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin or a polyamidoamine-epichlorohydrin must be selected not to render a resultant hydrophilic polymeric material water-insoluble (i.e., a solubility of less than 0.005 g per 100 ml of water at room temperature) and not to consume more than about 99%, preferably about 98%, more preferably about 97%, even more preferably about 96% of the azetidinium groups of the poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin or a polyamidoamine-epichlorohydrin.

In a preferred embodiment, a water-soluble and thermally-crosslinkable hydrophilic polymeric material having azetidinium groups comprises: azetidinium groups; from about 20% to about 95%, preferably from about 35% to about 90%, more preferably from about 50% to about 85%, by weight of first polymer chains derived from a poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin copolymer or a polyamidoamine-epichlorohydrin; and from about 5% to about 80%, preferably from about 10% to about 65%, even more preferably from about 15% to about 50%, by weight of hydrophilic moieties or second polymer chains derived from at least one hydrophilicity-enhancing agent having at least one reactive functional group selected from the group consisting of primary amino group, secondary amino group, carboxyl group, thiol group, and combination thereof.

In accordance with the invention, the step of heating is performed preferably by autoclaving the silicone hydrogel contact lens with a base coating thereon immersed in a packaging solution (i.e., a buffered aqueous solution) in a sealed lens package at a temperature of from about 115° C. to about 125° C. for approximately 20-90 minutes. In accordance with this embodiment of the invention, the packaging solution is a buffered aqueous solution which is ophthalmically safe after autoclave.

Lens packages (or containers) are well known to a person skilled in the art for autoclaving and storing a soft contact lens. Any lens packages can be used in the invention. Preferably, a lens package is a blister package which comprises a base and a cover, wherein the cover is detachably sealed to the base, wherein the base includes a cavity for receiving a sterile packaging solution and the contact lens.

Lenses are packaged in individual packages, sealed, and sterilized (e.g., by autoclave at about 120° C. or higher for at least 30 minutes under pressure) prior to dispensing to users. A person skilled in the art will understand well how to seal and sterilize lens packages.

In accordance with the invention, a packaging solution contains at least one buffering agent and one or more other ingredients known to a person skilled in the art. Examples of other ingredients include without limitation, tonicity agents, surfactants, antibacterial agents, preservatives, and lubricants (e.g., cellulose derivatives, polyvinyl alcohol, polyvinyl pyrrolidone).

The packaging solution contains a buffering agent in an amount sufficient to maintain a pH of the packaging solution in the desired range, for example, preferably in a physiologically acceptable range of about 6.5 to about 7.5. Any known, physiologically compatible buffering agents can be used. Suitable buffering agents as a constituent of the contact lens care composition according to the invention are known to the person skilled in the art. Examples are boric acid, borates, e.g. sodium borate, citric acid, citrates, e.g. potassium citrate, bicarbonates, e.g. sodium bicarbonate, TRIS (2-amino-2-hydroxymethyl-1,3-propanediol), Bis-Tris (Bis-(2-hydroxyethyl)-imino-tris-(hydroxymethyl)-methane), bis-aminopolyols, triethanolamine, ACES (N-(2-hydroxyethyl)-2-aminoethanesulfonic acid), BES (N,N-Bis(2-hydroxyethyl)-2-aminoethanesulfonic acid), HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid), MES (2-(N-morpholino)ethanesulfonic acid), MOPS (3-[N-morpholino]-propanesulfonic acid), PIPES (piperazine-N,N′-bis(2-ethanesulfonic acid), TES (N-[Tris(hydroxymethyl)methyl]-2-aminoethanesulfonic acid), salts thereof, phosphate buffers, e.g. Na₂HPO₄, NaH₂PO₄, and KH₂PO₄ or mixtures thereof. A preferred bis-aminopolyol is 1,3-bis(tris[hydroxymethyl]-methylamino)propane (bis-TRIS-propane). The amount of each buffer agent in a packaging solution is preferably from 0.001% to 2%, preferably from 0.01% to 1%; most preferably from about 0.05% to about 0.30% by weight.

The packaging solution has a tonicity of from about 200 to about 450 milliosmol (mOsm), preferably from about 250 to about 350 mOsm. The tonicity of a packaging solution can be adjusted by adding organic or inorganic substances which affect the tonicity. Suitable occularly acceptable tonicity agents include, but are not limited to sodium chloride, potassium chloride, glycerol, propylene glycol, polyols, mannitols, sorbitol, xylitol and mixtures thereof.

A packaging solution of the invention has a viscosity of from about 1 centipoise to about 8 centipoises, more preferably from about 1.5 centipoises to about 5 centipoises, at 25° C.

In a preferred embodiment, the packaging solution comprises preferably from about 0.01% to about 2%, more preferably from about 0.05% to about 1.5%, even more preferably from about 0.1% to about 1%, most preferably from about 0.2% to about 0.5%, by weight of a water-soluble thermally-crosslinkable hydrophilic polymeric material having azetidinium groups.

A silicone hydrogel contact lens obtained according to a method of the invention has a surface hydrophilicity/wettability characterized by having an averaged water contact angle of preferably about 90 degrees or less, more preferably about 80 degrees or less, even more preferably about 70 degrees or less, most preferably about 60 degrees or less.

A silicone hydrogel contact lens obtained according to a method of the invention has one property selected from the group consisting of: an oxygen permeability of at least about 40 barrers, preferably at least about 50 barrers, more preferably at least about 60 barrers, even more preferably at least about 70 barrers; an elastic modulus of about 1.5 MPa or less, preferably about 1.2 MPa or less, more preferably about 1.0 or less, even more preferably from about 0.3 MPa to about 1.0 MPa; a water content of from about 15% to about 70%, preferably from about 20% to about 65%, more preferably from about 25% to about 60%, even more preferably from about 30% to about 55% by weight when fully hydrated; a coating durability characterized by surviving a digital rubbing test; or combinations thereof.

The water content of a silicone hydrogel contact lens can be measured according to Bulk Technique as disclosed in U.S. Pat. No. 5,849,811.

Although various embodiments of the invention have been described using specific terms, devices, and methods, such description is for illustrative purposes only. The words used are words of description rather than of limitation. It is to be understood that changes and variations may be made by those skilled in the art without departing from the spirit or scope of the present invention, which is set forth in the following claims. In addition, it should be understood that aspects of the various embodiments may be interchanged either in whole or in part or can be combined in any manner and/or used together, as illustrated below:

-   1. A method for producing silicone hydrogel contact lenses each     having a crosslinked hydrophilic coating thereon, comprising the     steps of:     -   (a) obtaining a silicone hydrogel contact lens including a         polymer which is obtained by polymerizing a polymerizable         composition comprising         -   (i) at least one siloxane-containing vinylic monomer,         -   (ii) a polysiloxane vinylic crosslinker, and         -   (iii) at least about 25% by weight (preferably at least             about 30% by weight, more preferably at least about 35% by             weight, even more preferably at least about 40% by weight)             of one or more hydrophilic vinylic monomers relative to the             total amount of polymerizable components, wherein said one             or more hydrophilic vinylic monomers are selected from the             group consisting of N,N-dimethylacrylamide (DMA),             N,N-dimethylmethacrylamide (DMMA), 2-acrylamidoglycolic             acid, N-hydroxypropylacrylamide, N-hydroxyethyl acrylamide,             N-[tris(hydroxymethyl)methyl]-acrylamide,             N-vinylpyrrolidone, N-vinyl formamide, N-vinyl acetamide,             N-vinyl isopropylamide, N-vinyl-N-methyl acetamide,             N-methyl-3-methylene-2-pyrrolidone,             1-methyl-5-methylene-2-pyrrolidone,             5-methyl-3-methylene-2-pyrrolidone, and a combination             thereof;     -   (b) contacting the silicone hydrogel contact lens with an         organic solvent-based solution of polymethacrylic acid for a         time period of from about 30 seconds to about 120 seconds         (preferably from about 35 second to about 100 seconds, more         preferably from about 40 seconds to about 80 seconds) to form a         base coating;     -   (c) contacting the silicone hydrogel contact lens obtained in         step (b) with a polyamidoamine-epichlorohydrin solution for a         time period of from about 30 seconds to about 300 seconds         (preferably from about 35 second to about 200 seconds, more         preferably from about 40 seconds to about 120 seconds) to form a         polyamidoamine-epichlorohydrin-doped base coating on the         silicone hydrogel contact lens, wherein the         polyamidoamine-epichlorohydrin solution comprises from about         0.001% to about 5% by weight (preferably from about 0.01% to         about 2.5% by weight, more preferably from about 0.1% to about         1.5% by weight) of a polyamidoamine-epichlorohydrin dissolved in         water or in a mixture of water and an organic solvent relative         to the total weight of the polyamidoamine-epichlorohydrin         solution and having a pH of from about 2.0 to about 3.5         (preferably from about 2.0 to about 3.0, more preferably from         about 2.0 to about 2.5);     -   (d) heating the silicone hydrogel contact lens with the         polyamidoamine-epichlorohydrin-doped base coating thereon, which         is obtained in step (c), in an aqueous solution which comprises         a water-soluble and thermally-crosslinkable hydrophilic         polymeric material having azetidinium groups and optionally (but         preferably) amino or carboxyl groups, to and at a temperature of         from about 60° C. to about 140° C. for a time period sufficient         long to crosslink the polymethacrylic acid, the polyamidoamine         epichlorohydrin and the hydrophilic polymeric material, thereby         forming a hydrogel coating on the silicone hydrogel contact         lens,     -   wherein the hydrogel coating on the silicone hydrogel contact         lens has a durability as characterized by having a lubricity         better than the control coating on a control lens after being         subjected to 30 cycle of digital rubbing tests, wherein the         control lens is the silicone hydrogel contact lens and the         control coating on the control lens is obtained according to a         process in which only step (c) listed above is eliminated         whereas other steps and conditions listed above are unchanged. -   2. The method of invention 1, wherein the polymerizable composition     comprises at least about 30% by weight (preferably at least about     35% by weight, more preferably at least about 40% by weight) of one     or more hydrophilic vinylic monomers relative to the total amount of     polymerizable components, wherein said one or more hydrophilic     vinylic monomers are selected from the group consisting of     N,N-dimethylacrylamide (DMA), N,N-dimethylmethacrylamide (DMMA),     2-acrylamidoglycolic acid, N-hydroxypropylacrylamide, N-hydroxyethyl     acrylamide, N-[tris(hydroxymethyl)methyl]-acrylamide,     N-vinylpyrrolidone, N-vinyl formamide, N-vinyl acetamide, N-vinyl     isopropylamide, N-vinyl-N-methyl acetamide,     N-methyl-3-methylene-2-pyrrolidone,     1-methyl-5-methylene-2-pyrrolidone,     5-methyl-3-methylene-2-pyrrolidone, and a combination thereof. -   3. The method of invention 1 or 2, wherein the silicone hydrogel     contact lens is in contact with the organic solvent-based solution     of polymethacrylic acid for a time period of from about 35 second to     about 100 seconds (preferably from about 40 seconds to about 80     seconds) to form a base coating. -   4. The method according to any one of inventions 1 to 3, wherein the     silicone hydrogel contact lens obtained in step (b) is in contact     with the polyamidoamine-epichlorohydrin solution for a time period     of from about 35 second to about 200 seconds (preferably from about     40 seconds to about 120 seconds) to form a     polyamidoamine-epichlorohydrin-doped base coating on the silicone     hydrogel contact lens. -   5. The method according to any one of inventions 1 to 4, wherein the     polyamidoamine-epichlorohydrin solution comprises from about 0.01%     to about 2.5% by weight (preferably from about 0.1% to about 1.5% by     weight) of the polyamidoamine-epichlorohydrin dissolved in water or     in a mixture of water and an organic solvent relative to the total     weight of the polyamidoamine-epichlorohydrin solution. -   6. The method according to any one of inventions 1 to 5, wherein the     polyamidoamine-epichlorohydrin solution has a pH of from about 2.0     to about 3.0 (preferably from about 2.0 to about 2.5). -   7. The method according to any one of inventions 1 to 6, wherein the     water-soluble and thermally-crosslinkable hydrophilic polymeric     material has amino or carboxyl groups. -   8. The method according to any one of inventions 1 to 7, wherein     said one or more hydrophilic vinylic monomers are selected from the     group consisting of N,N-dimethylacrylamide (DMA),     N,N-dimethylmethacrylamide (DMMA), N-vinylpyrrolidone,     N-vinyl-N-methyl acetamide, N-methyl-3-methylene-2-pyrrolidone,     1-methyl-5-methylene-2-pyrrolidone,     5-methyl-3-methylene-2-pyrrolidone, and a combination thereof. -   9. The method according to any one of inventions 1 to 8, wherein the     polymethacrylic acid has a weight average molecular weight M_(w) of     at least about 10,000 Daltons, preferably at least about 50,000     Daltons, more preferably from about 100,000 Daltons to about     1,000,000 Daltons; -   10. The method according to any one of inventions 1 to 9, wherein     the concentration of polymethacrylic acid is from about 0.001% to     about 1.5%, preferably from about 0.002% to about 0.75%, more     preferably from 0.003% to about 0.1% by weight relative to the total     weight of the organic-based solution. -   11. The method according to any one of inventions 1 to 10, wherein     the organic solvent-based solution of polymethacrylic acid comprises     at least about 60% by weight of an organic solvent, preferably an     organic solvent or a mixture of one or more organic solvent. -   12. The method according to any one of inventions 1 to 11, wherein     the amount of carboxyl groups in the base coating is about 20     nanomoles or less per lens, preferably about 17.5 nanomoles or less     per lens, more preferably about 15 nanomoles or less per lens of     carboxyl groups. -   13. The method according to any one of inventions 1 to 12, wherein     the step of heating is carried out directly in a sealed lens package     containing a packaging solution including the water-soluble and     thermally-crosslinkable hydrophilic polymeric material during     sterilization by autoclave at a temperature from about 115° C. to     about 125° C. for at least about 20 minutes under pressure. -   14. The method of invention 13, wherein the packaging solution     comprises from about 0.01% to about 2% (preferably from about 0.05%     to about 1.5%, more preferably from about 0.1% to about 1%, even     more preferably from about 0.2% to about 0.5%) by weight of the     water-soluble and thermally-crosslinkable hydrophilic polymeric     material. -   15. The method of invention 13 or 14, wherein the packaging solution     comprises at least one buffering agent in an amount sufficient to     maintain a pH of from about 6.0 to about 8.5 and has a tonicity of     from about 200 to about 450 milliosmol (mOsm) (preferably from about     250 to about 350 mOsm) and a viscosity of from about 1 centipoise to     about 8 centipoises (preferably from about 1.5 centipoises to about     5 centipoises) at 25° C. -   16. The method according to any one of inventions 1 to 15, wherein     the water-soluble and thermally crosslinkable hydrophilic polymeric     material comprises:     -   (i) from about 20% to about 95% by weight of first polymer         chains derived from a polyamidoamine-epichlorohydrin or a         poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin;     -   (ii) from about 5% to about 80% by weight of hydrophilic         moieties or second polymer chains derived from at least one         hydrophilicity-enhancing agent having at least one reactive         functional group selected from the group consisting of amino         group, carboxyl group, thiol group, and combination thereof; and     -   (iii) positively-charged azetidinium groups which are parts of         the first polymer chains or pendant or terminal groups         covalently attached to the first polymer chains, wherein the         hydrophilic moieties or second polymer chains are covalently         attached to the first polymer chains through one or more         covalent linkages each formed between one azetidinium group of         the polyamidoamine-epichlorohydrin or the         poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin and one         amino, carboxyl or thiol group of the hydrophilicity-enhancing         agent. -   17. The method according invention 16, wherein the water-soluble and     thermally crosslinkable hydrophilic polymeric material comprises     from about 35% to about 90% (preferably from about 50% to about 85%)     by weight of first polymer chains derived from a     polyamidoamine-epichlorohydrin or a     poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin. -   18. The method according invention 16 or 17, wherein the     water-soluble and thermally crosslinkable hydrophilic polymeric     material comprises from about 10% to about 65% (more preferably from     about 15% to about 50%) by weight of hydrophilic moieties or second     polymer chains derived from at least one hydrophilicity-enhancing     agent having at least one reactive functional group selected from     the group consisting of amino group, carboxyl group, thiol group,     and combination thereof. -   19. The method of any one of inventions 16 to 18, wherein the     hydrophilicity-enhancing agent is a hydrophilic polymer having one     or more amino, carboxyl and/or thiol groups, wherein the content of     the amino, carboxyl and/or thiol groups in the hydrophilic polymer     as the hydrophilicity-enhancing agent is less than about 40%,     preferably less than about 30%, more preferably less than about 20%,     even more preferably less than about 10%, by weight based on the     total weight of the hydrophilic polymer. -   20. The method of according to any one of inventions 16 to 19,     wherein the hydrophilic polymer as the hydrophilicity-enhancing     agent is: PEG-N H₂; PEG-SH; PEG-COOH; H₂N-PEG-NH₂; HOOC-PEG-COOH;     HS-PEG-SH; H₂N-PEG-COOH; HOOC-PEG-SH; H₂N-PEG-SH; multi-arm PEG with     one or more amino, carboxyl or thiol groups; PEG dendrimers with one     or more amino, carboxyl or thiol groups; a diamino-, dicarboxyl-,     monoamino- or monocarboxyl-terminated homo- or co-polymer of a     non-reactive hydrophilic vinylic monomer; or combinations thereof,     wherein PEG is a polyethylene glycol segment, wherein the     non-reactive vinylic monomer is selected from the group consisting     of acrylamide, methacrylamide, N,N-dimethylacrylamide,     N,N-dimethylmethacrylamide, N-vinylpyrrolidone,     N,N,-dimethylaminoethylmethacrylate, N,N-dimethylaminoethylacrylate,     N,N-dimethylaminopropylmethacrylamide,     N,N-dimethylaminopropylacrylamide, glycerol methacrylate,     3-acryloylamino-1-propanol, N-hydroxyethyl acrylamide,     N-[tris(hydroxymethyl)methyl]-acrylamide,     N-methyl-3-methylene-2-pyrrolidone,     1-ethyl-3-methylene-2-pyrrolidone,     1-methyl-5-methylene-2-pyrrolidone,     1-ethyl-5-methylene-2-pyrrolidone,     5-methyl-3-methylene-2-pyrrolidone,     5-ethyl-3-methylene-2-pyrrolidone, 2-hydroxyethyl (meth)acrylate,     hydroxypropyl (meth)acrylate, a phosphorylcholine-containing vinylic     monomer, C₁-C₄-alkoxy polyethylene glycol (meth)acrylate having a     weight average molecular weight of up to 1500 Daltons, N-vinyl     formamide, N-vinyl acetamide, N-vinyl isopropylamide,     N-vinyl-N-methyl acetamide, allyl alcohol, vinyl alcohol (hydrolyzed     form of vinyl acetate in the copolymer), and combinations thereof. -   21. The method of according to any one of inventions 16 to 19,     wherein the hydrophilic polymer as the hydrophilicity-enhancing     agent is a copolymer which is a polymerization product of a     composition comprising (1) about 60% by weight or less, preferably     from about 0.1% to about 30%, more preferably from about 0.5% to     about 20%, even more preferably from about 1% to about 15%, by     weight of at least one reactive vinylic monomer and (2) at least one     non-reactive hydrophilic vinylic monomer, wherein the reactive     vinylic monomer is selected from the group consisting of amino-C₁-C₆     alkyl (meth)acrylate, C₁-C₆ alkylamino-C₁-C₆ alkyl (meth)acrylate,     allylamine, vinylamine, amino-C₁-C₆ alkyl (meth)acrylamide, C₁-C₆     alkylamino-C₁-C₆ alkyl (meth)acrylamide, acrylic acid, C₁-C₄     alkylacrylic acid, N,N-2-acrylamidoglycolic acid,     beta-methyl-acrylic acid, alpha-phenyl acrylic acid, beta-acryloxy     propionic acid, sorbic acid, angelic acid, cinnamic acid,     1-carboxy-4-phenyl butadiene-1,3, itaconic acid, citraconic acid,     mesaconic acid, glutaconic acid, aconitic acid, maleic acid, fumaric     acid, tricarboxy ethylene, and combinations thereof;     -   wherein the non-reactive vinylic monomer is selected from the         group consisting of acrylamide, methacrylamide,         N,N-dimethylacrylamide, N,N-dimethylmethacrylamide,         N-vinylpyrrolidone, N,N,-dimethylaminoethylmethacrylate,         N,N-dimethylaminoethylacrylate,         N,N-dimethylaminopropylmethacrylamide,         N,N-dimethylaminopropylacrylamide, glycerol methacrylate,         3-acryloylamino-1-propanol, N-hydroxyethyl acrylamide,         N-[tris(hydroxymethyl)methyl]-acrylamide,         N-methyl-3-methylene-2-pyrrolidone,         1-ethyl-3-methylene-2-pyrrolidone,         1-methyl-5-methylene-2-pyrrolidone,         1-ethyl-5-methylene-2-pyrrolidone,         5-methyl-3-methylene-2-pyrrolidone,         5-ethyl-3-methylene-2-pyrrolidone, 2-hydroxyethyl         (meth)acrylate, hydroxypropyl (meth)acrylate, a         phosphorylcholine-containing vinylic monomer, C₁-C₄-alkoxy         polyethylene glycol (meth)acrylate having a weight average         molecular weight of up to 1500 Daltons, N-vinyl formamide,         N-vinyl acetamide, N-vinyl isopropylamide, N-vinyl-N-methyl         acetamide, allyl alcohol, vinyl alcohol (hydrolyzed form of         vinyl acetate in the copolymer), and combinations thereof. -   22. The method of according to any one of inventions 16 to 18, The     method of claim 6, wherein the hydrophilic polymer as the     hydrophilicity-enhancing agent is an amino- or carboxyl-containing     polysaccharide, hyaluronic acid, chondroitin sulfate, and     combinations thereof. -   23. The method of according to any one of inventions 16 to 22,     wherein the weight average molecular weight M_(w) of the hydrophilic     polymer as the hydrophilicity-enhancing agent is from about 500 to     about 1,000,000, preferably from about 1,000 to about 500,000, even     more preferably from about 5,000 to about 250,000 Daltons, -   24. The method of according to any one of inventions 16 to 18,     wherein the hydrophilicity-enhancing agent is: amino-, carboxyl- or     thiol-containing monosaccharides; amino-, carboxyl- or     thiol-containing disaccharides; and amino-, carboxyl- or     thiol-containing oligosaccharides. -   25. The method of according to any one of inventions 16 to 24,     wherein the first polymer chains are derived from the     polyamidoamine-epichlorohydrin. -   26. The method of according to any one of inventions 16 to 24,     wherein the first polymer chains are derived from the     poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin. -   27. A silicone hydrogel contact lens produced according to the     method of any one of inventions 1 to 26. -   28. The silicone hydrogel contact lens of invention 27, wherein the     silicone hydrogel contact lens has a surface     hydrophilicity/wettability characterized by having an averaged water     contact angle of preferably about 90 degrees or less, more     preferably about 80 degrees or less, even more preferably about 70     degrees or less, most preferably about 60 degrees or less. -   29. The silicone hydrogel contact lens of invention 27 or 28,     wherein the silicone hydrogel contact lens has one property selected     from the group consisting of: an oxygen permeability of at least     about 40 barrers; an elastic modulus of from about 0.3 MPa to about     1.0 MPa; a water content of from about 15% to about 70% by weight     when fully hydrated; a coating durability characterized by surviving     a digital rubbing test; or combinations thereof.

All patents, patent applications, and publications referred to or cited herein are incorporated by reference in their entirety, including all figures and tables, to the extent they are not inconsistent with the explicit teachings of this specification.

It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application.

Example 1 Oxygen Permeability Measurements

The apparent oxygen permeability (Dk_(app)), the apparent oxygen transmissibility (Dk/t), the intrinsic (or edge-corrected) oxygen permeability (Dk_(c)) of a lens and a lens material are determined according to procedures described in Example 1 of U.S. patent application publication No. 2012/0026457 A1.

Digital Rubbing Tests.

The lenses are digitally rubbed (wearing disposable powder-free latex gloves) with RENU® multi-purpose lens care solution (or another multi-purpose lens care solution) for 20 seconds and then rinsed with saline. The above procedure is repeated for a given times, e.g., from 1 to 30 times, (i.e., number of repetitions of digital rubbing tests which imitate cleaning and soaking cycles).

Lubricity Evaluation.

The lubricity rating is a qualitative ranking scheme where 0 is assigned to control lenses coated with DAILIES® TOTAL1® commercial lenses, 1 is assigned to OASYS™/TruEye™ commercial lenses and 4 is assigned to commercial AIR OPTIX® lenses. The samples are placed in PBS for at least two rinses of 30 minutes each and then transferred to fresh PBS before the evaluation. Before the evaluation, hands are rinsed with a soap solution, extensively rinsed with DI water and then dried with KimWpe® towels. The samples are handled between the fingers and a numerical number is assigned for each sample relative to the above standard lenses described above. For example, if lenses are determined to be only slightly better than AIR OPTIX® lenses, then they are assigned a number 3.

Surface Hydrophilicity/Wettability Tests.

Water contact angle on a contact lens is a general measure of the surface hydrophilicity (or wettability) of the contact lens. In particular, a low water contact angle corresponds to more hydrophilic surface. Average contact angles (Sessile Drop) of contact lenses are measured using a VCA 2500 XE contact angle measurement device from AST, Inc., located in Boston, Mass. This equipment is capable of measuring advancing or receding contact angles or sessile (static) contact angles. The measurements are performed on fully hydrated contact lenses and immediately after blot-drying as follows. A contact lens is removed from the vial and washed 3 times in ˜200 ml of fresh DI water in order to remove loosely bound packaging additives from the lens surface. The lens is then placed on top of a lint-free clean cloth (Alpha Wipe TX1009), dabbed well to remove surface water, mounted on the contact angle measurement pedestal, blown dry with a blast of dry air and finally the sessile drop contact angle is automatically measured using the software provided by the manufacturer. The DI water used for measuring the contact angle has a resistivity>18MΩcm and the droplet volume used is 41. Typically, uncoated silicone hydrogel lenses (after autoclave) have a sessile drop contact angle around 120 degrees. The tweezers and the pedestal are washed well with Isopropanol and rinsed with DI water before coming in contact with the contact lenses.

Water Break-Up Time (WBUT) Tests.

The wettability of the lenses (after autoclave) is also assessed by determining the time required for the water film to start breaking on the lens surface. Briefly, lenses are removed from the vial and placed in PBS for at least two rinses of 30 minutes each and then transferred to fresh PBS in order to remove loosely bound packaging additives from the lens surface. The lens is removed from the solution and held against a bright light source. The time that is needed for the water film to break (de-wet) exposing the underlying lens material is noted visually. Uncoated lenses typically instantly break upon removal from PBS and are assigned a WBUT of 0 seconds. Lenses exhibiting WBUT≧10 seconds are considered wettable and are expected to exhibit adequate wettability (ability to support the tear film) on-eye.

Coating Intactness Tests.

The intactness of a coating on the surface of a contact lens can be tested according to Sudan Black stain test as follow. Contact lenses with a coating (an LbL coating, a plasma coating, or any other coatings) are dipped into a Sudan Black dye solution (Sudan Black in vitamin E oil). Sudan Black dye is hydrophobic and has a great tendency to be adsorbed by a hydrophobic material or onto a hydrophobic lens surface or hydrophobic spots on a partially coated surface of a hydrophobic lens (e.g., silicone hydrogel contact lens). If the coating on a hydrophobic lens is intact, no staining spots should be observed on or in the lens. All of the lenses under test are fully hydrated.

Example 2

Phosphate Solution (0.2%, pH 2). A phosphate solution (0.2%, pH 2) is prepared by dissolving 2 grams of sodium phosphate dibasic dehydrate in 998 grams of DI water and the pH is adjusted to 2.0 by adding 1N HCL. Phosphate Solution (0.1%, pH 2). A phosphate solution (0.1%, pH 2) is prepared by diluting from the Phosphate Solution (0.2%, pH 2) prepared above. Bicarbonate Solution (0.2%, pH 10). A bicarbonate solution (0.2%, pH 10) is prepared by dissolving 2 grams of sodium bicarbonate in 998 grams of DI water and the pH is adjusted to 10.0 by adding 1N NaOH. Bicarbonate Solution (0.1%, pH 10). A bicarbonate solution (0.1%, pH 10) is prepared by diluting from the Bicarbonate Solution (0.2%, pH 2) prepared above. TBO Stock Solution (2000 ppm). A TBO stock solution (2000 ppm) is prepared by dissolving 0.04 gram of Toluidine Blue 0 (TBO) (from Sigma Aldrich) in 20 grams of DI water. TBO Staining Solution (50 ppm). A TBO staining solution (50 ppm) is prepared by diluting the TBO Stock Solution prepared above, e.g., by combining 0.5 g of the TBO stock solution with 19.5 g of the bicarbonate solution (0.1%, pH 10). The solution is kept covered until ready for use. Calibration Solutions. A series of TBO calibration solutions are prepared by diluting the TBO stock solution with the phosphate solution (0.1%, pH 2) to have the following concentrations: 0.5 ppm; 1 ppm; 2 ppm; 4 ppm; 8 ppm; 10 ppm; and 100 ppm. Calibration. Pipette in 1.5 ml of the TBO calibration solutions (0 to 8 ppm) in duplicates in rows ‘B’ and ‘C’ of a new 24-well TOPS plate. Load the plate with the TBO calibration solutions in a spectrophotometer (SpectraMax M3, from Molecular Devices), read the absorbance of each wells, and establish a calibration curve. Essay of carboxyl groups per lens. Each lens to be analyzed is rinsed for ˜5 min in 100 ml of DI water per lens to remove packaging additives (all lenses from one group are rinsed using a single beaker with the appropriate DI water volume). Then, the lenses are removed from the beaker and the excess water is gently blotted away using Alpha wipe synthetic wipers. Place the lenses in a 24-well TOPS plate (one lens per well). Pipette in 1.5 ml of the 50 pm stain solution into each well and place the plate on the VWR digital block heater which is set at 50° C. and covered with aluminum foil for faster and uniform heating. After 30 minutes of heating, the lenses are removed from the staining plate and placed in new wells of a 24-wells TOPS plate (one lens per well). Pipette in fresh 1.5 ml of the bicarbonate solution (0.1%, pH 10) and the leave the lenses at room temperature for 5 min. Then, remove the lenses and place them in new wells of a 24-well TOPS plate. Pipette in fresh 1.5 ml of the bicarbonate solution (0.1%, pH 10) and leave the plate on the block heater set at 35° C. for 30 min. Remove the lenses from the wells and gently blot away the excess stain using the Alpha wipe synthetic wipers. Place the lenses into wells from rows “B” and “C” of a new 24-well TOPS plate and pipette in 1.5 ml of the phosphate solution (0.1%, pH 2). Leave the plate on the block heater set at 50° C. for 30 min. The bound dye is released from the lenses during this step. Remove the lens from the well and the left-over solutions are ready for UV-VIS analysis. Load the plate with the left-over solutions in a spectrophotometer (SpectraMax M3, from Molecular Devices), read the absorbance of each wells, and determine the concentration of TBO released from each lens into 1.5 ml of the phosphate solution (0.1%, pH 2) based on the obtained calibration curve. Convert the concentration into nanomoles of carboxyl groups per lens based on 1:1 TBO:carboxyl group ratio).

Example 3 Preparation of CE-PDMS Macromer

In the first step, α,ω-bis(2-hydroxyethoxypropyl)-polydimethylsiloxane (Mn=2000, Shin-Etsu, KF-6001a) is capped with isophorone diisocyanate (IPDI) by reacting 49.85 g of α,ω-bis(2-hydroxyethoxypropyl)-polydimethylsiloxane with 11.1 g IPDI in 150 g of dry methyl ethyl ketone (MEK) in the presence of 0.063 g of dibutyltindilaurate (DBTDL). The reaction is kept for 4.5 h at 40° C., forming IPDI-PDMS-IPDI. In the second step, a mixture of 164.8 g of α,ω-bis(2-hydroxyethoxypropyl)-polydimethylsiloxane (Mn=3000, Shin-Etsu, KF-6002) and 50 g of dry MEK are added dropwise to the IPDI-PDMS-IPDI solution to which has been added an additional 0.063 g of DBTDL. The reactor is held for 4.5 h at about 40° C., forming HO-PDMS-IPDI-PDMS-IPDI-PDMS-OH. MEK is then removed under reduced pressure. In the third step, the terminal hydroxyl-groups are capped with methacryloyloxyethyl groups in a third step by addition of 7.77 g of isocyanatoethylmethacrylate (IEM) and an additional 0.063 g of DBTDL, forming IEM-PDMS-IPDI-PDMS-IPDI-PDMS-IEM (i.e., CE-PDMS terminated with methacrylate groups).

Alternate Preparation of CE-PDMS Macromer with Terminal Methacrylate Groups

240.43 g of KF-6001 is added into a 1-L reactor equipped with stirring, thermometer, cryostat, dropping funnel, and nitrogen/vacuum inlet adapter, and then dried by application of high vacuum (2×10⁻² mBar). Then, under an atmosphere of dry nitrogen, 320 g of distilled MEK is then added into the reactor and the mixture is stirred thoroughly. 0.235 g of DBTDL is added to the reactor. After the reactor is warmed to 45° C., 45.86 g of IPDI are added through an addition funnel over 10 minutes to the reactor under moderate stirring. The reaction is kept for 2 hours at 60° C. 630 g of KF-6002 dissolved in 452 g of distilled MEK are then added and stirred until a homogeneous solution is formed. About 0.235 g of DBTDL is added, and the reactor is held at about 55° C. overnight under a blanket of dry nitrogen. The next day, MEK is removed by flash distillation. The reactor is cooled and 22.7 g of IEM are then charged to the reactor followed by about 0.235 g of DBTDL. After about 3 hours, an additional 3.3 g of IEM are added and the reaction is allowed to proceed overnight. The following day, the reaction mixture is cooled to about 18° C. to obtain CE-PDMS macromer with terminal methacrylate groups.

Preparation of Lens Formulations

A lens formulation is prepared by dissolving components in 1-propanol to have the following composition: about 32% by weight of CE-PDMS macromer prepared above, about 21% by weight of N-[tris(trimethylsiloxy)-silylpropyl]acrylamide (TRIS-Am), about 23% by weight of N,N-dimethylacrylamide (DMA), about 0.6% by weight of N-(carbonyl-methoxypolyethylene glycol-2000)-1,2-disteaoyl-sn-glycero-3-phosphoethanolamin, sodium salt) (L-PEG), about 1% by weight of Darocur 1173 (DC1173), about 0.1% by weight of visitint (5% copper phthalocyanine blue pigment dispersion in tris(trimethylsiloxy)silylpropylmethacrylate, TRIS), about 0.8% by weight of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), about 200 ppm of 1-hydroxy-2,2,6,6-tetramethyl-piperidine (H-tempo), and about 22% by weight of 1-propanol.

Preparation of Uncoated Contact Lenses

Lenses are prepared by cast-molding from the lens formulation prepared above in a reusable mold (quartz female mold half and glass male mold half), similar to the mold shown in FIGS. 1-6 in U.S. Pat. Nos. 7,384,590 and 7,387,759 (FIGS. 1-6). The lens formulation in the molds is irradiated with UV irradiation (13.0 mW/cm²) for about 24 seconds. Cast-molded contact lenses are then extracted by dipping in the following series of baths: DI water bath (about 56 seconds); 6 MEK baths (about 44, 56, 56, 56, 56, and 56 second respectively).

Example 4

PMAA-coating solution. A polymethacrylic acid (PMAA) coating solution is prepared by dissolving an amount of PMAA (M.W.: 300-600 kDa, from Polysciences, Inc.) in a given volume of 1-propanol/water (90%/10% wt/wt) mixture to have a concentration of about 0.011% by weight and the pH is adjusted with formic acid to about 2.0. PAE solution I. A PAE solution is prepared by dissolving an amount of polyamidoamine epichlorohydrin (Kymene) in a given volume of water to have a concentration of about 0.5% by weight and the pH is adjusted to a desired pH (e.g., 2.0, 3.5, 7, or 9). PAE solution II. A PAE solution is prepared by dissolving an amount of polyamidoamine epichlorohydrin (Kymene) in a given volume of a mixture of water (68% by weight) and 1-propanol (32% by weight) to have a concentration of about 0.5% by weight and the pH is adjusted to pH 2.0. 

What is claimed is:
 1. A method for producing silicone hydrogel contact lenses each having a crosslinked hydrophilic coating thereon, comprising the steps of: (a) obtaining a silicone hydrogel contact lens including a polymer which is a polymerization product of a polymerizable composition comprising (i) at least one siloxane-containing vinylic monomer, (ii) a polysiloxane vinylic crosslinker, and (iii) at least about 25% by weight of one or more hydrophilic vinylic monomers relative to the total amount of polymerizable components, wherein said one or more hydrophilic vinylic monomers are selected from the group consisting of N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, 2-acrylamidoglycolic acid, N-hydroxypropylacrylamide, N-hydroxyethyl acrylamide, N-[tris(hydroxymethyl)methyl]-acrylamide, N-vinylpyrrolidone, N-vinyl formamide, N-vinyl acetamide, N-vinyl isopropylamide, N-vinyl-N-methyl acetamide, N-methyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone, 5-methyl-3-methylene-2-pyrrolidone, and a combination thereof; (b) contacting the silicone hydrogel contact lens with an organic solvent-based solution of polymethacrylic acid for a time period of from about 30 seconds to about 120 seconds to form a base coating; (c) contacting the silicone hydrogel contact lens obtained in step (b) with a polyamidoamine-epichlorohydrin solution for a time period of from about 30 seconds to about 300 seconds to form a polyamidoamine-epichlorohydrin-doped base coating on the silicone hydrogel contact lens, wherein the polyamidoamine-epichlorohydrin solution comprises from about 0.001% to about 5% by weight of a polyamidoamine-epichlorohydrin dissolved in water or in a mixture of water and an organic solvent relative to the total weight of the polyamidoamine-epichlorohydrin solution and having a pH of from about 2.0 to about 3.5; (d) heating the silicone hydrogel contact lens with the polyamidoamine-epichlorohydrin-doped base coating thereon, which is obtained in step (c), in an aqueous solution which comprises a water-soluble and thermally-crosslinkable hydrophilic polymeric material having azetidinium groups and optionally amino or carboxyl groups, to and at a temperature of from about 60° C. to about 140° C. for a time period sufficient long to crosslink the polymethacrylic acid, the polyamidoamine epichlorohydrin and the hydrophilic polymeric material, thereby forming a hydrogel coating on the silicone hydrogel contact lens, wherein the hydrogel coating on the silicone hydrogel contact lens has a durability as characterized by having a lubricity better than the control coating on a control lens after being subjected to 30 cycle of digital rubbing tests, wherein the control lens is the silicone hydrogel contact lens and the control coating on the control lens is obtained according to a process in which only step (c) listed above is eliminated whereas other steps and conditions listed above are unchanged.
 2. The method of claim 1, wherein said one or more hydrophilic vinylic monomers are selected from the group consisting of N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-vinylpyrrolidone, N-vinyl-N-methyl acetamide, N-methyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone, 5-methyl-3-methylene-2-pyrrolidone, and a combination thereof.
 3. The method of claim 2, wherein the polymethacrylic acid has a weight average molecular weight M_(w) of at least about 10,000 Daltons; wherein the concentration of polymethacrylic acid is from about 0.001% to about 1.5% by weight relative to the total weight of the organic-based solution; wherein the organic solvent-based solution of polymethacrylic acid comprises at least about 60% by weight of an organic solvent.
 4. The method of claim 3, wherein the amount of carboxyl groups in the base coating is about 20 nanomoles or less per lens.
 5. The method of claim 1, wherein the polymethacrylic acid has a weight average molecular weight M_(w) of at least about 10,000 Daltons; wherein the concentration of polymethacrylic acid is from about 0.001% to about 1.5% by weight relative to the total weight of the organic-based solution; wherein the organic solvent-based solution of polymethacrylic acid comprises at least about 60% by weight of an organic solvent.
 6. The method of claim 3, wherein the step of heating is carried out directly in a sealed lens package containing a packaging solution including the water-soluble and thermally-crosslinkable hydrophilic polymeric material during sterilization by autoclave at a temperature from about 115° C. to about 125° C. for at least about 20 minutes under pressure; wherein the packaging solution comprises from about 0.01% to about 2% by weight of the water-soluble and thermally-crosslinkable hydrophilic polymeric material; wherein the packaging solution comprises at least one buffering agent in an amount sufficient to maintain a pH of from about 6.0 to about 8.5 and has a tonicity of from about 200 to about 450 milliosmol (mOsm), and a viscosity of from about 1 centipoise to about 8 centipoises, at 25° C.
 7. The method of claim 6, wherein the water-soluble and thermally crosslinkable hydrophilic polymeric material comprises: (i) from about 20% to about 95% by weight of first polymer chains derived from a polyamidoamine-epichlorohydrin or a poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin; (ii) from about 5% to about 80% by weight of hydrophilic moieties or second polymer chains derived from at least one hydrophilicity-enhancing agent having at least one reactive functional group selected from the group consisting of amino group, carboxyl group, thiol group, and combination thereof; and (iii) positively-charged azetidinium groups which are parts of the first polymer chains or pendant or terminal groups covalently attached to the first polymer chains, wherein the hydrophilic moieties or second polymer chains are covalently attached to the first polymer chains through one or more covalent linkages each formed between one azetidinium group of the polyamidoamine-epichlorohydrin or the poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin and one amino, carboxyl or thiol group of the hydrophilicity-enhancing agent.
 8. The method of claim 7, wherein the hydrophilicity-enhancing agent is a hydrophilic polymer having one or more amino, carboxyl and/or thiol groups, wherein the content of the amino, carboxyl and/or thiol groups in the hydrophilic polymer as the hydrophilicity-enhancing agent is less than about 40% by weight based on the total weight of the hydrophilic polymer.
 9. The method of claim 7, wherein the hydrophilic polymer as the hydrophilicity-enhancing agent is: PEG-N H₂; PEG-SH; PEG-COOH; H₂N-PEG-NH₂; HOOC-PEG-COOH; HS-PEG-SH; H₂N-PEG-COOH; HOOC-PEG-SH; H₂N-PEG-SH; multi-arm PEG with one or more amino, carboxyl or thiol groups; PEG dendrimers with one or more amino, carboxyl or thiol groups; a diamino-, dicarboxyl-, monoamino- or monocarboxyl-terminated homo- or co-polymer of a non-reactive hydrophilic vinylic monomer; or combinations thereof, wherein PEG is a polyethylene glycol segment, wherein the non-reactive vinylic monomer is selected from the group consisting of acrylamide, methacrylamide, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-vinylpyrrolidone, N,N,-dimethylaminoethylmethacrylate, N,N-dimethylaminoethylacrylate, N,N-dimethylaminopropylmethacrylamide, N,N-dimethylaminopropylacrylamide, glycerol methacrylate, 3-acryloylamino-1-propanol, N-hydroxyethyl acrylamide, N-[tris(hydroxymethyl)methyl]-acrylamide, N-methyl-3-methylene-2-pyrrolidone, 1-ethyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone, 1-ethyl-5-methylene-2-pyrrolidone, 5-methyl-3-methylene-2-pyrrolidone, 5-ethyl-3-methylene-2-pyrrolidone, 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, a phosphorylcholine-containing vinylic monomer, C₁-C₄-alkoxy polyethylene glycol (meth)acrylate having a weight average molecular weight of up to 1500 Daltons, N-vinyl formamide, N-vinyl acetamide, N-vinyl isopropylamide, N-vinyl-N-methyl acetamide, allyl alcohol, vinyl alcohol (hydrolyzed form of vinyl acetate in the copolymer), and combinations thereof.
 10. The method of claim 7, wherein the hydrophilic polymer as the hydrophilicity-enhancing agent is a copolymer which is a polymerization product of a composition comprising (1) about 60% by weight or less by weight of at least one reactive vinylic monomer and (2) at least one non-reactive hydrophilic vinylic monomer, wherein the reactive vinylic monomer is selected from the group consisting of amino-C₁-C₆ alkyl (meth)acrylate, C₁-C₆ alkylamino-C₁-C₆ alkyl (meth)acrylate, allylamine, vinylamine, amino-C₁-C₆ alkyl (meth)acrylamide, C₁-C₆ alkylamino-C₁-C₆ alkyl (meth)acrylamide, acrylic acid, C₁-C₄ alkylacrylic acid, N,N-2-acrylamidoglycolic acid, beta-methyl-acrylic acid, alpha-phenyl acrylic acid, beta-acryloxy propionic acid, sorbic acid, angelic acid, cinnamic acid, 1-carboxy-4-phenyl butadiene-1,3, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, maleic acid, fumaric acid, tricarboxy ethylene, and combinations thereof; wherein the non-reactive vinylic monomer is selected from the group consisting of acrylamide, methacrylamide, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-vinylpyrrolidone, N,N,-dimethylaminoethylmethacrylate, N,N-dimethylaminoethylacrylate, N,N-dimethylaminopropylmethacrylamide, N,N-dimethylaminopropylacrylamide, glycerol methacrylate, 3-acryloylamino-1-propanol, N-hydroxyethyl acrylamide, N-[tris(hydroxymethyl)methyl]-acrylamide, N-methyl-3-methylene-2-pyrrolidone, 1-ethyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone, 1-ethyl-5-methylene-2-pyrrolidone, 5-methyl-3-methylene-2-pyrrolidone, 5-ethyl-3-methylene-2-pyrrolidone, 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, a phosphorylcholine-containing vinylic monomer, C₁-C₄-alkoxy polyethylene glycol (meth)acrylate having a weight average molecular weight of up to 1500 Daltons, N-vinyl formamide, N-vinyl acetamide, N-vinyl isopropylamide, N-vinyl-N-methyl acetamide, allyl alcohol, vinyl alcohol (hydrolyzed form of vinyl acetate in the copolymer), and combinations thereof.
 11. The method of claim 7, wherein the hydrophilic polymer as the hydrophilicity-enhancing agent is an amino- or carboxyl-containing polysaccharide, hyaluronic acid, chondroitin sulfate, and combinations thereof.
 12. The method of claim 7, wherein the weight average molecular weight M_(w) of the hydrophilic polymer as the hydrophilicity-enhancing agent is from about 500 to about 1,000,000 Daltons,
 13. The method of claim 7, wherein the hydrophilicity-enhancing agent is: amino-, carboxyl- or thiol-containing monosaccharides; amino-, carboxyl- or thiol-containing disaccharides; and amino-, carboxyl- or thiol-containing oligosaccharides.
 14. The method of claim 7, wherein the first polymer chains are derived from the polyamidoamine-epichlorohydrin.
 15. The method of claim 7, wherein the first polymer chains are derived from the poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin.
 16. The method of claim 5, wherein the step of heating is carried out directly in a sealed lens package containing a packaging solution including the water-soluble and thermally-crosslinkable hydrophilic polymeric material during sterilization by autoclave at a temperature from about 115° C. to about 125° C. for at least about 20 minutes under pressure; wherein the packaging solution comprises from about 0.01% to about 2% by weight of the water-soluble and thermally-crosslinkable hydrophilic polymeric material; wherein the packaging solution comprises at least one buffering agent in an amount sufficient to maintain a pH of from about 6.0 to about 8.5 and has a tonicity of from about 200 to about 450 milliosmol (mOsm), and a viscosity of from about 1 centipoise to about 8 centipoises, at 25° C.
 17. The method of claim 16, wherein the water-soluble and thermally crosslinkable hydrophilic polymeric material comprises: (i) from about 20% to about 95% by weight of first polymer chains derived from a polyamidoamine-epichlorohydrin or a poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin; (ii) from about 5% to about 80% by weight of hydrophilic moieties or second polymer chains derived from at least one hydrophilicity-enhancing agent having at least one reactive functional group selected from the group consisting of amino group, carboxyl group, thiol group, and combination thereof; and (iii) positively-charged azetidinium groups which are parts of the first polymer chains or pendant or terminal groups covalently attached to the first polymer chains, wherein the hydrophilic moieties or second polymer chains are covalently attached to the first polymer chains through one or more covalent linkages each formed between one azetidinium group of the polyamidoamine-epichlorohydrin or the poly(2-oxazoline-co-ethyleneimine)-epichlorohydrin and one amino, carboxyl or thiol group of the hydrophilicity-enhancing agent.
 18. The method of claim 17, wherein the hydrophilicity-enhancing agent is a hydrophilic polymer having one or more amino, carboxyl and/or thiol groups, wherein the content of the amino, carboxyl and/or thiol groups in the hydrophilic polymer as the hydrophilicity-enhancing agent is less than about 40% by weight based on the total weight of the hydrophilic polymer.
 19. The method of claim 17, wherein the hydrophilic polymer as the hydrophilicity-enhancing agent is: PEG-N H₂; PEG-SH; PEG-COOH; H₂N-PEG-NH₂; HOOC-PEG-COOH; HS-PEG-SH; H₂N-PEG-COOH; HOOC-PEG-SH; H₂N-PEG-SH; multi-arm PEG with one or more amino, carboxyl or thiol groups; PEG dendrimers with one or more amino, carboxyl or thiol groups; a diamino-, dicarboxyl-, monoamino- or monocarboxyl-terminated homo- or co-polymer of a non-reactive hydrophilic vinylic monomer; or combinations thereof, wherein PEG is a polyethylene glycol segment, wherein the non-reactive vinylic monomer is selected from the group consisting of acrylamide, methacrylamide, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-vinylpyrrolidone, N,N,-dimethylaminoethylmethacrylate, N,N-dimethylaminoethylacrylate, N,N-dimethylaminopropylmethacrylamide, N,N-dimethylaminopropylacrylamide, glycerol methacrylate, 3-acryloylamino-1-propanol, N-hydroxyethyl acrylamide, N-[tris(hydroxymethyl)methyl]-acrylamide, N-methyl-3-methylene-2-pyrrolidone, 1-ethyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone, 1-ethyl-5-methylene-2-pyrrolidone, 5-methyl-3-methylene-2-pyrrolidone, 5-ethyl-3-methylene-2-pyrrolidone, 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, a phosphorylcholine-containing vinylic monomer, C₁-C₄-alkoxy polyethylene glycol (meth)acrylate having a weight average molecular weight of up to 1500 Daltons, N-vinyl formamide, N-vinyl acetamide, N-vinyl isopropylamide, N-vinyl-N-methyl acetamide, allyl alcohol, vinyl alcohol (hydrolyzed form of vinyl acetate in the copolymer), and combinations thereof.
 20. The method of claim 17, wherein the hydrophilic polymer as the hydrophilicity-enhancing agent is a copolymer which is a polymerization product of a composition comprising (1) about 60% by weight or less by weight of at least one reactive vinylic monomer and (2) at least one non-reactive hydrophilic vinylic monomer, wherein the reactive vinylic monomer is selected from the group consisting of amino-C₁-C₆ alkyl (meth)acrylate, C₁-C₆ alkylamino-C₁-C₆ alkyl (meth)acrylate, allylamine, vinylamine, amino-C₁-C₆ alkyl (meth)acrylamide, C₁-C₆ alkylamino-C₁-C₆ alkyl (meth)acrylamide, acrylic acid, C₁-C₄ alkylacrylic acid, N,N-2-acrylamidoglycolic acid, beta-methyl-acrylic acid, alpha-phenyl acrylic acid, beta-acryloxy propionic acid, sorbic acid, angelic acid, cinnamic acid, 1-carboxy-4-phenyl butadiene-1,3, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, maleic acid, fumaric acid, tricarboxy ethylene, and combinations thereof; wherein the non-reactive vinylic monomer is selected from the group consisting of acrylamide, methacrylamide, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-vinylpyrrolidone, N,N,-dimethylaminoethylmethacrylate, N,N-dimethylaminoethylacrylate, N,N-dimethylaminopropylmethacrylamide, N,N-dimethylaminopropylacrylamide, glycerol methacrylate, 3-acryloylamino-1-propanol, N-hydroxyethyl acrylamide, N-[tris(hydroxymethyl)methyl]-acrylamide, N-methyl-3-methylene-2-pyrrolidone, 1-ethyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone, 1-ethyl-5-methylene-2-pyrrolidone, 5-methyl-3-methylene-2-pyrrolidone, 5-ethyl-3-methylene-2-pyrrolidone, 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, a phosphorylcholine-containing vinylic monomer, C₁-C₄-alkoxy polyethylene glycol (meth)acrylate having a weight average molecular weight of up to 1500 Daltons, N-vinyl formamide, N-vinyl acetamide, N-vinyl isopropylamide, N-vinyl-N-methyl acetamide, allyl alcohol, vinyl alcohol (hydrolyzed form of vinyl acetate in the copolymer), and combinations thereof. 